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Introduction: Otitis Media with Effusion (OME) occurs as a sequelae of adenoid hypertrophy. But most often hearing loss due to OME goes unnoticed in children. This causes poor cognitive development, inattention and thus poor scholastic performance. Aim: To estimate the frequency of asymptomatic OME in children with adenoid hypertrophy and to find the association between adenoid size and occurrence of OME and hearing loss. Materials and Methods: This prospective cross-sectional study was conducted in a tertiary care centre in South India, from November 2019 to November 2021. Children of 5-12 years of age, with symptoms suggestive of adenoid hypertrophy and with no complaints of hearing loss, were selected. A detailed ear, nose, throat examination, Pure Tone Audiometry (PTA) and tympanometry were done in all patients. Adenoid size was graded by nasal endoscopy using Mc Murray and Clements scale and also based on radiographs {comparing the distance between maximum convexity of adenoid and line drawn along basiocciput (A) and posterior part of hard palate and sphenobasioccipital synchondrosis (N)} using A/N ratio. All patients subsequently underwent adenoidectomy. Myringotomy was done along with adenoidectomy in cases with bilateral OME. All OME patients were followed-up with tympanometry, one month and three months postoperatively. The frequency of OME was presented as percentage. The association between adenoid size and asymptomatic OME as well as hearing loss was done using Fisher’s exact test. Results: A total of 150 children, aged between 5-12 years with adenoid hypertrophy were analysed. The mean age was 9 years. On analysing the association between adenoid size (both radiographically and endoscopically) and OME, 30 (20%) had bilateral effusion, 18 (12%) had unilateral effusion and prevalence of asymptomatic OME was calculated as 32%. Most of the patients had grade II adenoids radiographically, and grade III adenoids as per nasal endoscopy. Majority of patients had Type B Tympanogram. There was significant association between OME and adenoid size. Association between adenoid size with hearing loss showed significant association between the two with p-value=0.001 on right ear and p-value

Recent studies highlight the role of brain metabolites in regulation of neuronal signals and behaviour. To understand the underlying mechanism, brain metabolites and associated signaling molecules were examined in early adolescent rat experienced CRS. Rats were tested for their learning and memory ability, and their metabolite profile was evaluated using Gas chromatography-mass spectrometry (GC-MS). Differences in metabolites were examined by variable importance in projection (VIP) and multivariate analysis. Ingenuity Pathway Analysis (IPA) and KEGG ID were performed for the identified metabolites. We found that CRS altered the metabolites that were involved in biosynthesis of steroid hormone, aminoacyl t-RNA, L-Dopa biosynthesis, and metabolism of tyrosine, fatty acid, and purine. Further analysis showed reduction of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR, a metabolite involved in purine metabolism) an AMP kinase activator, influenced the hypoxanthine-guanine phosphoribosyltransferase (HPRT), serotonin transporter (SERT), postsynaptic density protein (PSD) -95, its phosphorylation and brain-derived neurotrophic factor (BDNF) in CRS animals, which displayed deficit in memory. The AICAR treated CRS rats showed improved memory and altered metabolites and other molecules (HPRT, SERT, PSD-95 and BDNF) levels were restored. Our analysis revealed that CRS induced changes in metabolites possibly altered synaptic plasticity and memory in which HPRT, SERT-PSD95-BDNF associated pathway involved. Taken together, our observation provides initial insight into how stress differently influences the metabolic pathway, and associated behaviour. Further study will help to develop pharmacological intervention strategies., Competing Interests: Declarations Ethical Approval The experimental protocol reviewed and approved by Institutional Animal Ethics Committee (Ref. No.: BDU/IAEC/P28/2024), assuring that the number of animals used was minimum. Competing Interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Environmental enrichment (EE) through combination of social and non-biological stimuli enhances activity-dependent synaptic plasticity and improves behavioural performance. Our earlier studies have suggested that EE resilience the stress induced depression/ anxiety-like behaviour in Indian field mice Mus booduga. This study was designed to test whether EE reverses the social isolation (SI) induced effect and improve memory. Field-caught mice M. booduga were subjected to behaviour test (Direct wild, DW), remaining animals were housed under SI for ten days and then housed for short-term at standard condition (STSC)/ long-term at standard condition (LTSC) or as group in EE cage. Subsequently, we have examined reference, working memory and expression of genes associated with synaptic plasticity. Our analysis have shown that EE reversed SI induced impairment in reference, working memory and other accompanied changes i.e. increased level of Intersectin 1 (ITSN1), Huntingtin (Htt), Synaptotagmin -IV (SYT4), variants of brain-derived neurotrophic factor (Bdnf - III), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (GluR1) expression, and decreased variants of Bdnf (IV), BDNF, Reelin, Apolipoprotein E receptor 2 (ApoER2), very low-density lipoprotein receptor (VLDLR), Src family tyrosine kinase (SFKs), Disabled protein (Dab)-1, Protein kinase B (PKB/Akt), GluR2, Mitogen-activated protein kinase (MAPK) and Extracellular signal-regulated kinase (ERK1/2) expression. In addition, SI induced reduction in BDNF expressing neurons in dentate gyrus of hippocampus reversed by EE. Further, we found that SI decreases small neuro-active molecules such as Benzenedicarboxylic acid, and increases 2-Pregnene in the hippocampus and feces reversed by EE. Overall, this study demonstrated that EE is effectively reversed the SI induced memory impairment by potentially regulating the molecules associated with the ITSN1-Reelin-AMPA receptor pathway to increase synaptic plasticity., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sowndharya, Rajan. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Maternal stress (MS) during gestation is known to increase the risk for the development of behavioural and physiological disorders and advances cellular aging. In this study, we investigated whether the supplementation of standardized Bacopa monnieri extract (CDRI-08/BME) or l-Carnosine (L-C) to the mother exposed to social stress during gestation modify the effect on their offspring's neurobehaviour, antioxidant defence gene expression, telomere length, and telomere biology. To test this, timed pregnant rats were subjected to social stress during the gestational day (GD) 16-18. A subset of stressed pregnant rats received either BME [80 mg/kg in 0.5% gum acacia (per-orally; p.o)] or L-C [1 mg/kg (p.o)] every day from GD-10 to until their pup's attained postnatal day (PND)-23. We observed that MS induced anxiety-like behaviour, altered inter-limb coordination, antioxidant defence genes [Superoxide dismutase (SOD1,2), Catalase (CAT), Glutathione peroxidase-3 (GPX3)], telomerase reverse transcriptase (TERT), shelterin complex subunits (TRF1, RAP1B, POT1) protein level and shorten telomere length. Notably, supplementation of BME/L-C dampens the MS, thus the effect on neurobehaviour, antioxidant defence gene expression, and telomere biology is minimized in their offspring. Together, our results suggest that supplementation of BME/L-C during gestation dampens the MS and reduced oxidative stress-mediated changes in telomere shortening/biology and associated neurobehaviour in offspring born following MS., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Background and Aim: Rat pups emit ultrasound vocalizations (USVs) in response to negative/positive stimuli, the acoustic features of USVs are altered during the stressful and threatening situation. We hypothesize that maternal separation (MS) and/or stranger (St) exposure would alter acoustic features of USVs, neurotransmitter transmission, epigenetic status and impaired odor recognition later in life., Method: Rat pups were left undisturbed in the home cage (a) control, (b) pups were separated from mother MS [postnatal day (PND) 5-10], (c) intrusion of stranger (St; social experience: SE) to the pups either in the presence of mother (M + P + St) or (d) absence of mother (MSP + St). USVs was recorded on PND10 in two context i) five minutes after MS, MS and St, mother with their pups and St, ii) five minutes after the pups reunited with their pups and/or removal of stranger. Novel odor preference test was conducted during their mid-adolescence on PND34, 35., Results: Rat pups produced two complex USVs (frequency step-down: 38-48 kHz; and two syllable: 42-52 kHz) especially when the mother was absent and the stranger was present. Further, pups failed to recognize novel odor, which can be linked to an increased dopamine transmission, decreased transglutaminase (TGM)-2, increased histone trimethylation (H3K4me3) and dopaminylation (H3Q5dop) in the amygdala., Conclusions: This result suggest that USVs act as acoustic code of different early-life stressful social experience, which appears to have long-term effect on odor recognition, dopaminergic activity and dopamine dependent epigenetic status., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The present study was aimed to examine the behavioural and molecular alterations in experimental meningitis survivor rat model. On postnatal day (PND)-2, animals were assigned to different groups: (i) Control (Ctrl), (ii) Positive Control [PCtrl: gavaged with Luria-Bertani (LB) broth on PND-2 and received antibiotics treatment (AbT) from PND-5 to 11], (iii) Cronobacter sakazakii (CS: received single dose of live bacterial culture on PND-2) infected. Later, a subset of CS group received antibiotics treatment (AbT) from PND-5 to 11 and assigned as group (iv) (CS + AbT/ survivor). On PND-35, animals were subjected to behavioural tasks [viz., elevated plus maze (EPM) test and step-through inhibitory retention], and sacrificed for molecular analyses. We found that CS infection induces anxiety-like behaviour, impaired short/long-term memory and differentially altered the expression of brain-derived neurotrophic factor (BDNF) splice variants (III, IV and VI), decreased expression of BDNF, Src family tyrosine kinase (FYN), focal adhesion kinase (FAK) and nerve growth factor (NGF). The observed behavioural phenotype and expression pattern of candidate genes fit in the correlation. In addition, NGF expression was reduced in dentate gyrus (DG) and CA1 regions of hippocampus. Notably, antibiotic treatment reduced the anxiety-like behaviour, improved step-through inhibitory retention and suppressed infection induced reduction in BDNF, FYN, FAK and NGF expressions in survivors, however, not comparable to the control group. Overall, our experimental meningitis survivor model demonstrate that antibiotic treatment minimize the C. sakazakii infection induced effect on behaviour and signaling molecules involving in neuronal development, survival, and synaptic plasticity, but the consequences are long-term., Competing Interests: Declaration of Competing Interest Authors declared no conflict of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Maternal exposure to anti-epileptic drug Valproic acid (VPA) during pregnancy increases the risk for the development of autism spectrum disorders (ASD). In this study, we have examined whether prenatal exposure to VPA will alter expression of key genes, synaptic morphology of nerve growth factor (NGF) and Reelin expressing neurons in the cortex of male offspring. To characterize in animal models, rat fetuses were exposed to VPA on 12.5 gestational day. The offspring of the VPA-exposed individuals (42%) resembles ASD-related phenotype (facial malformation, crooked-like tail, flattened paw, toenails and in-turning-ankles). Furthermore, we have observed deficit in social interaction accompanied by deregulation in expression of genes such as Caspase-3, focal adhesion kinase (FAK), Reelin, glial fibrillary acidic protein (GFAP), proliferating cell nuclear antigen (PCNA) and NGF. Subsequently, immunohistochemistry analysis revealed that exposure to VPA alters the cytoarchitecture (area, diameter) and reduced the dendritic arborization of Reelin, NGF expressing neurons in cortex. The compromised neurodevelopment by altered expression of Caspase-3, FAK, Reelin, GFAP, PCNA and NGF may cause defects in neuronal architecture, synaptic formation, synaptic plasticity and neuronal communication which could be linked with observed ASD-like phenotype and deficit social interaction., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The purpose of this study was to examine whether the Cronobacter sakazakii infection-induced inflammation alters the Reelin signaling pathway that is involved in learning and memory. To test this, postnatal day (PND)-15 rat pups were either treated with Luria Bertani broth/Escherichia coli OP50/C. sakazakii through oral gavage or maintained as control and allowed to stay with their mothers until PND-24. Experimental groups' rats were subjected to long-term novel object recognition test during their adolescent age PND-30-32. Observed behavioral data showed that C. sakazakii infection causes a deficit in recognition of novel objects from known objects. Further, our analysis showed that C. sakazakii infection-mediated inflammation decreases the Reelin expression by proteolytic cleavage and alters its receptor apolipoprotein E-receptor (ApoER)-2 splice variants ApoER2 (ex19) and ApoER2 (Δ). Subsequently, downregulated Reelin alters the phosphorylation of disabled adapter protein (Dab)-1 and leads to differential expression of N-methyl-D-aspartate (NMDA) receptor subunits 2A and 2B. Further, the NMDA receptor influences the expression of postsynaptic density (PSD)-95 protein and brain-derived neurotrophic factor (BDNF). Observed results suggest a deficit in recognition of novel objects possibly due to the alternation in Reelin signaling pathway., (© 2022 S. Karger AG, Basel.)

This study was designed to test whether Cynopterus sphinx distress calls influence olfactory learning and memory in conspecifics. Bats were exposed to distress calls/playbacks (PBs) of distress calls/modified calls and were then trained to novel odors. Bats exposed to distress calls/PBs made significantly fewer feeding attempts and bouts of PBs exposed to modified calls, which significantly induced the expression of c-Fos in the caudomedial neostriatum (NCM) and the amygdala compared to bats exposed to modified calls and trained controls. However, the expression of c-Fos in the hippocampus was not significantly different between the experimental groups. Further, protein phosphatase-1 (PP-1) expression was significantly lower, and the expression levels of E1A homologue of CREB-binding protein (CBP) (P300), brain-derived neurotrophic factor (BDNF) and its tyrosine kinase B1 (TrkB1) receptor were significantly higher in the hippocampus of control/bats exposed to modified calls compared to distress calls/PBs of distress call-exposed bats. Exposure to the call possibly alters the reciprocal interaction between the amygdala and the hippocampus, accordingly regulating the expression levels of PP1, P300 and BDNF and its receptor TrkB1 following training to the novel odor. Thus, the learning and memory consolidation processes were disrupted and showed fewer feeding attempts and bouts. This model may be helpful for understanding the contributions of stressful social communications to human disorders., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study was designed to investigate stressful social experience (SSE) in early life by examining how it can induce alterations in the microbiota-gut-brain axis. To test this, different experimental groups of pups experienced the presence of either a stranger (S) with mother (M+P+S) or without their mother (MS+S-M). Animals were assessed for anxiety-like behavior and high-throughput bacterial 16s rRNA sequencing was performed to analyze the structure of the gut microbiota. Our analysis revealed that early life SSE induced anxiety-like behavior and reduced the diversity and richness of gut microbiota. In the second experiment, all groups were supplemented with Lactobacillus paracasei HT6 . The findings indicated that Lactobacillus supplementation had a significant beneficial effect on anxiety-like behavior in stressed rats (MS, M+P+S, and MS + S-M) accompanied by normalized levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT), glucocorticoid receptor (GR), serotonin (5-HT), dopamine (DA), and noradrenaline (NA). Concomitantly, the expression of microRNA (miR)-124a was down-regulated and miR-132, caspase-3, glutamate receptors (GluR1, GluR 2; NR2A, and NR2B) were up-regulated in stressed groups but remained unchanged by Lactobacillus supplementation in stressed individuals. This indicates that stress-associated GluR1-GR altered interactions can be significantly prevented by Lactobacillus supplementation. Analysis of the fecal metabolite profile was undertaken to analyze the effect of Lactobacillus , revealing that five predicted neuroactive microbial metabolites were reduced by early life SSE. Our results showed a potential link between Lactobacillus supplementation and beneficial effects on anxiety-like behavior, the mechanism of which could be potentially mediated through stress hormones, neurotransmitters, and expression of miRNAs, glutamate receptors, and the microbiota-gut-brain axis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Karen, Shyu and Rajan.)

This study was designed to test whether the Cronobacter sakazakii infection-impaired contextual learning and memory are mediated by the activation of the complement system; subsequent activation of inflammatory signals leads to alternations in serotonin transporter (SERT). To test this, rat pups (postnatal day, PND 15) were treated with either C. sakazakii (10 7  CFU) or Escherichia coli OP50 (10 7  CFU) or Luria bertani broth (100 μL) through oral gavage and allowed to stay with their mothers until PND 24. Experimental groups' rats were allowed to explore (PNDs 31-35) and then trained in contextual learning task (PNDs 36-43). Five days after training, individuals were tested for memory retention (PNDs 49-56). Observed behavioural data showed that C. sakazakii infection impaired contextual-associative learning and memory. Furthermore, our analysis showed that C. sakazakii infection activates complement system complement anaphylatoxin (C5a) (a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS1)) and mitogen-activated protein kinase kinase1 (MEKK1). Subsequently, MEKK1 induces pro-inflammatory signals possibly through apoptosis signal-regulating kinase-1 (ASK-1), c-Jun N-terminal kinase (JNK1/3) and protein kinase B gamma (AKT-3). In parallel, activated nuclear factor kappa-light-chain-enhancer B cells (NF-κB) induces interleukin-6 (IL-6) and IFNα-1, which may alter the level of serotonin transporter (SERT). Observed results suggest that impaired contextual learning and memory could be correlated with C5a-mediated NF-κβ and ASK1 pathways.

Social defeat (SD) has been implicated in different modulatory effects of physiology and behaviour including learning and memory. We designed an experiment to test the functional role of monoamine oxidase (MAO) in regulation of synaptic transmission, synaptic plasticity and memory in goldfish Carassius auratus. To test this, individuals were divided into three groups: (i) control; (ii) social defeat (SD) group (individuals were subjected to social defeat for 10 min by Pseudotropheus demasoni) and (iii) SD + MAO inhibitor pre-treated group. All experimental groups were subjected to spatial learning and then memory. Our results suggest that SD affects a spatial learning and memory, whereas SD exerts no influence on MAOI pre-treated group. In addition, we noted that the expression of monoamine oxidase-A (MAO-A) was up-regulated and level of serotonin (5-hydroxytryptamine; 5-HT), expression of serotonin transporter (SERT), synaptophysin (SYP), synaptotagmin -1 (SYT-1), N-methyl-D-asparate (NMDA) receptors subunits (NR2A and NR2B), postsynaptic density-95 (PSD-95) and brain-derived neurotrophic factor (BDNF) were reduced by SD, while MAOIs pretreatment protects the effect of SD. Taken together, our results suggest that MAO is an essential component in the serotonergic system that finely tunes the level of 5-HT, which further regulates the molecules involving in synaptic transmission, synaptic plasticity and memory., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Environmental enrichment (EE) dynamically regulates gene expression and synaptic plasticity with positive consequences on behavior. The present study was performed on field-mice to explore the effects of EE on both captive-condition inducing social stress and epigenetic changes of molecules resilience stress. For this purpose, field-mice were caught and allowed to habituate in standard laboratory conditions for 7 days. The next day animals were randomly assigned to three groups: i) mice at short-term standard condition (STSC); which were subjected to social interaction test (SIT) on day 9, ii) mice continuously maintainedfor additional 30 days, with these long-term standard conditions (LTSC), and iii) mice maintained in an EE cage for additional 30 days. After achieving SIT, we examined epigenetic changes of a repertory of molecules associated with resilience stress, by determining their levels by Western blot. Thus, the main findings were that during SIT, EE exerted more social interaction of field-mice with the strangers compared with STSC and LTSC mice. Related with social behavior results, we found that in mice subjected to EE the levels of histone 3 lysine 9 di-methylation (H3K9me2), glucocorticoid receptor (GR), N-methyl-D asparate (NMDA) receptor subunits NR2A and NR2B, postsynaptic density protein-95 (PSD-95), and mature brain-derived neurotrophic factor (mBDNF) were significantly elevated; whereas the levels of DNA methyltransferase-3A (DNMT3A), methyl-CpG-binding protein-2 (MeCP2), repressor element-1 silencing transcription factor (REST), H3K4me2 and lysine demethylase-1A (KDM1A) decreased. These results suggest that enhanced sociability of EE mice could be mediated, in part, by altered expression of molecules regulating glutamate signaling pathway through GR by epigenetic mechanisms., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Prenatal stress (PNS) influences offspring neurodevelopment, inducing anxiety-like behavior and memory deficits. We investigated whether pretreatment of Bacopa monnieri extract (CDRI-08/BME) ameliorates PNS-induced changes in signaling molecules, and changes in the behavior of Wistar rat offspring. Pregnant rats were randomly assigned into control (CON)/prenatal stress (PNS)/PNS and exposed to BME treatment (PNS + BME). Dams were exposed to stress by placing them in a social defeat cage, where they observed social defeat from gestational day (GD)-16-18. Pregnant rats in the PNS + BME group were given BME treatment from GD-10 to their offspring's postnatal day (PND)-23, and to their offspring from PND-15 to -30. PNS led to anxiety-like behavior; impaired memory; increased the level of corticosterone (CORT), adrenocorticotropic hormone, glucocorticoid receptor, pro-apoptotic Casepase-3, and 5-HT 2C receptor; decreased anti-apoptotic Bcl-2, synaptic proteins (synaptophysin, synaptotagmin-1), 5-HT 1A, receptor, phosphorylation of calmodulin-dependent protein kinase II/neurogranin, N -methyl-D-aspartate receptors (2A,2B), postsynaptic density protein 95; and conversion of pro and mature brain derived neurotropic factor in their offspring. The antioxidant property of BME possibly inhibiting the PNS-induced changes in observed molecules, anxiety-like behavior, and memory deficits. The observed results suggest that pretreatment of BME could be an effective coping strategy to prevent PNS-induced behavioral impairments in their offspring.

Early-life experiences have been linked to individual's epigenetic status and social behaviour. Therefore, the present study aims to test whether the presence of mother suppress the early-life stressful social experience (SSE)-induced effect on social behaviour of adolescent and adult rats, and associated epigenetic changes. To test this, experimental groups [maternally separated pups (MSP)/pups with their mother (M+P)] were allowed to experience the presence of a stranger (ST), and then their social behaviour was compared with the maternal separated (MS) and control (Con) group. We observed that MS, MSP-ST group showed less social interaction with the unknown conspecifics than known conspecifics compared to other groups. Subsequently, we found that SSE elevated the level of DNA methyltransferases (Dnmt3a), ten-eleven translocation (Tet3), methyl-CpG-binding protein-2 (MeCP2) and Repressor Element-1 Silencing Transcription Factor (REST) in amygdala of adolescent and adult MS, MSP-ST groups compared to other groups. As expected, SSE altered the histone (H3) lysine (K14/K9) acetylation (ac) and H3K4/K9 methylation (me2/me3). SSE decreased the level of H3K14ac and H3K9ac in adolescents and then increased in adults. Interestingly, H3K4me2/me3 levels were elevated in adolescent and adults. Whereas H3K9me2/me3 shows contrasting pattern in adolescent, but H3K9me2/me3 levels were increased in adults. In addition, the expression of brain-derived neurotrophic factor (BDNF) was reduced in MS, MSP-ST groups' adolescent and adult rats. Observed correlation between epigenetic changes and social behaviour possibly contributed by early-life SSE in the absence of mother, but mother's presence suppresses the effect of early-life SSE.

In this study, we examined whether the presence of mother suppresses early-life stressful social experience (SSE)-induced anxiety-like behavior and impairment of short-term memory later in life. On postnatal day (PND)-5, mothers with pups were grouped as follows: (i) control; (ii) maternal separation (MS); (iii) pups with mother experience the presence of a stranger (M+P-ST); and (iv) maternal separated pups experience the presence of a stranger (MSP-ST). Individuals were subjected to light-dark box and spontaneous alternation from PND-29 to 32. We observed that the MSP-ST group exhibits anxiety-like behavior and impairment in short-term memory. Further, SSE significantly elevated the adrenocorticotropic hormone, corticosterone and expression of glucocorticoid receptor (GR) in MSP-ST pups. Similarly, serotonin (5-hydroxytryptamine; 5-HT), dopamine, noradrenaline and expression of serotonin transporter levels were significantly elevated in MSP-ST pups. These observations suggest that during early postnatal days, the pups may recognize strangers by the sense of smell, and the presence of mother reduces the SSE-induced stress., (© 2019 S. Karger AG, Basel.)

Earlier, we showed that micro RNA-132 (miR-132) regulate the immediate early genes (IEGs) in the olfactory bulb (OB) of fruit bat Cynopterus sphinx during olfactory learning. This study was designed to examine whether the miR-132 regulate other proteins in OB during olfactory learning. To test this, miR-132 anti-sense oligodeoxynucleotide (AS-ODN) was delivered to the OB and then trained to novel odor. The 2-dimensional gel electrophoresis analysis showed that inhibition of miR-132 altered olfactory training induced expression of 321 proteins. Further, liquid chromatography-mass spectrometry (LC-MS/MS) analysis reveals the identity of differently expressed proteins such as phosphoribosyl transferase domain containing protein (PRTFDC 1), Sorting nexin-8 (SNX8), Creatine kinase B-type (CKB) and Annexin A11 (ANX A11). Among them PRTFDC 1 showing 189 matching peptides with highest sequence coverage (67.0%) and protein-protein interaction analysis showed that PRTFDC 1 is a homolog of hypoxanthine phosphoribosyltransferase-1 (HPRT-1). Subsequent immunohistochemical analysis (IHC) showed that inhibition of miR-132 down-regulated HPRT expression in OB of C. sphinx. In addition, western blot analysis depicts that HPRT, serotonin transporter (SERT), N-methyl-d-asparate (NMDA) receptors (2A,B) were down-regulated, but not altered in OB of non-sense oligodeoxynucleotide (NS-ODN) infused groups. These analyses suggest that miR-132 regulates the process of olfactory learning and memory formation through SERT and NMDA receptors signalling, which is possibly associated with the PRTFDC1-HPRT interaction., (Copyright © 2018. Published by Elsevier B.V.)

Background: Earlier, we showed that nicotinamide (NAM) treatment impairs spatial memory through the downregulation of CREB-Sirt 1-brain-derived neurotrophic factor ( Bdnf ) signaling cascade., Purpose: In this study, we examine whether NAM treatment alters CREB-regulated genes through -microRNAs., Method: To test this hypothesis, goldfish ( Carassius auratus ) were divided into 2 groups: (i) vehicle group (VEH; double distilled water intra-peritoneally [i.p.]) (ii) nicotinamide group (NAM, 1,000 mg/kg, i.p.) and again divided into VEH untrained/trained, NAM untrained/trained. One hour after receiving VEH or NAM, individuals were subject to contextual fear conditioning (CFC) training. After 24 h, both the groups were tested for contextual fear memory. Subsequently, miR-132/212 levels, regulated immediate-early genes (IEGs: C-fos and EGR-1) and Bdnf but not its receptor. -TrkB1were examined following 0' and 60' min after training, and compared with the untrained group., Results: We observed that NAM treatment significantly impaired fear memory. Further, the analysis showed that miR-132 level was not altered, but miR-212 level was significantly upregulated after CFC training only in NAM-treated fish. We also found that NAM treatment downregulated IEGs and Bdnf but not its receptor TrkB1., Conclusions: Present study suggests that NAM-treatment impaired fear memory and control IEGs, Bdnf and TrkB1 expression by differentially regulating miR-132 and 212.

Activity-dependent expression of immediate-early genes (IEGs) is induced by exposure to odour. The present study was designed to investigate whether there is differential expression of IEGs ( Egr-1 , C-fos ) in the brain region mediating olfactory memory in the Indian greater short-nosed fruit bat, Cynopterus sphinx We assumed that differential expression of IEGs in different brain regions may orchestrate a preference odour (PO) and aversive odour (AO) memory in C. sphinx We used preferred (0.8% w/w cinnamon powder) and aversive (0.4% w/v citral) odour substances, with freshly prepared chopped apple, to assess the behavioural response and induction of IEGs in the olfactory bulb, hippocampus and amygdala. After experiencing PO and AO, the bats initially responded to both, later only engaging in feeding bouts in response to the PO food. The expression pattern of EGR-1 and c-Fos in the olfactory bulb, hippocampus and amygdala was similar at different time points (15, 30 and 60 min) following the response to PO, but was different for AO. The response to AO elevated the level of c-Fos expression within 30 min and reduced it at 60 min in both the olfactory bulb and the hippocampus, as opposed to the continuous increase noted in the amygdala. In addition, we tested whether an epigenetic mechanism involving protein phosphatase-1 (PP-1) acts on IEG expression. The observed PP-1 expression and the level of unmethylated/methylated promoter revealed that C-fos expression is possibly controlled by odour-mediated regulation of PP-1. These results in turn imply that the differential expression of C-fos in the hippocampus and amygdala may contribute to olfactory learning and memory in C. sphinx ., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)

Bacopa monniera extract (CDRI-08; BME) has been known to improve learning and memory, and understanding the molecular mechanisms may help to know its specificity. We investigated whether the BME treatment alters the methylation status of reelin and brain-derived neurotropic factor (BDNF) to enhance the memory through the interaction of N-methyl-D-aspartate receptor (NMDAR) with synaptic proteins. Rat pups were subjected to novel object recognition test following daily oral administration of BME (80 mg/kg) in 0.5% gum acacia (per-orally, p.o.; PND 15-29)/three doses of 5-azacytidine (5-azaC; 3.2 mg/kg) in 0.9% saline (intraperitoneally, i.p.) on PND-30. After the behavioral test, methylation status of reelin, BDNF and activation of NMDAR, and its interactions with synaptic proteins were tested. Rat pups treated with BME/5-azaC showed higher discrimination towards novel objects than with old objects during testing. Further, we observed an elevated level of unmethylated DNA in reelin and BDNF promoter region. Up-regulated reelin along with the splice variant of apolipoprotein E receptor 2 (ApoER 2, ex 19) form a cluster and activate NMDAR through disabled adopter protein-1 (DAB1) to enhance BDNF. Observed results suggest that BME regulate reelin epigenetically, which might enhance NMDAR interactions with synaptic proteins and induction of BDNF. These changes may be linked with improved novel object recognition memory.

We conducted a set of playback experiments aimed at understanding whether distress-call structure in the greater short-nosed fruit bat Cynopterus sphinx is specific in encoding information relating to stress that attracts conspecifics. We tested the specificity by playing their distress call and its modified version at a foraging site for free-ranging bats, as well as under captive conditions involving either a small group or individuals. In a separate playback experiment, bats showed a significantly greater response when the natural call as opposed to a modified call was played back to captive as well as free-ranging bats at the foraging site. Under captive conditions, bats showed less of a response to the playback of distress calls when in a group than when alone. We subsequently found that tyrosine hydroxylase (TH) and its transcription factor-nuclear receptor related factor 1 (Nurr-1); and the dopamine transporter (DAT) and its receptor (D1DR) were elevated significantly in the amygdala of bats both emitting and responding to a distress call, but not in the case of bats responding to the modified call. These results suggest that distress-call structure encodes information on the state of stress that is capable of being conveyed to conspecifics.

It is well established that Cronobacter sakazakii infection cause septicemia, necrotizing enterocolitis and meningitis. In the present study, we tested whether the C. sakazakii infection alter the learning and memory through serotonin transporter (SERT). To investigate the possible effect on SERT, on postnatal day-15 (PND-15), wistar rat pups were administered with single dose of C. sakazakii culture (infected group; 10(7) CFU) or 100 μL of Luria-Bertani broth (medium control) or without any treatment (naïve control). All the individuals were subjected to passive avoidance test on PND-30 to test their fear memory. We show that single dose of C. sakazakii infection improved fear memory retention. Subsequently, we show that C. sakazakii infection induced the activation of toll-like receptor-3 and heat-shock proteins-90 (Hsp-90). On the other hand, level of serotonin (5-hydroxytryptamine) and SERT protein was down-regulated. Furthermore, we show that C. sakazakii infection up-regulate microRNA-16 (miR-16) expression. The observed results highlight that C. sakazakii infections was responsible for improved fear memory retention and may have reduced the level of SERT protein, which is possibly associated with the interaction of up-regulated Hsp-90 with SERT protein or miR-16 with SERT mRNA. Taken together, observed results suggest that C. sakazakii infection alter the fear memory possibly through SERT. Hence, this model may be effective to test the C. sakazakii infection induced changes in synaptic plasticity through SERT and effect of other pharmacological agents against pathogen induced memory disorder.

Earlier, we reported spatial learning ability in goldfish (Carassius auratus) by using spatial paradigm with food reward. Therefore, we hypothesized that goldfish may use associated cue to integrate "where" and "what" for spatial memory. To test our hypothesis, we first trained goldfish to learn to cross the gate1, which is associated with spatial task. Subsequently, they were trained to learn to enter the task chamber and to identify the food reward chamber associated with visual cue (red/green light). Red and green lights were positioned randomly for each trial but always the food reward was kept in green chamber. In addition, to elucidate the role of the signalling cascade in spatial memory associated with visual cue, nicotinamide (NAM, 1000 mg/kg, i.p), a NAD(+) precursor, was used to inhibit the Sirtuin 1 (SIRT1) cyclic AMP response element binding protein (CREB) pathway. Fishes were trained for 5 days in a maze after treating with either vehicle (VEH, DD H2O) or NAM, and then, they were individually tested for memory. We found that VEH-treated fish learned and recalled the task successfully by showing less latency and making more correct choices than NAM-treated group. Subsequent analysis showed that NAM treatment significantly down-regulated the phosphorylation of extracellular signal-regulated kinase (ERK1/2), CREB, expression of SirT1 and brain-derived neurotrophic factor (Bdnf) in telencephalon. Taken together, our results provide behavioural evidence of spatial memory associated with visual cue in C. auratus, which could be regulated by ERK1/2-CREB-SirT1-Bdnf pathway.

Exposure to a predator elicits an innate fear response and mimics several behavioral disorders related to post-traumatic stress disorder (PTSD). The protective role of an enriched condition (EC) against psychogenic stressors in various animal models has been well documented. However, this condition has not been tested in field mice in the context of PTSD. In this study, we show that field mice (Mus booduga) housed under EC exhibit predominantly proactive and less reactive behavior compared with mice housed under standard conditions (SC) during exposure to their natural predator (field rat Rattus rattus). Furthermore, we observed that EC mice displayed less anxiety-like behavior in an elevated plus maze (EPM) and light/dark-box after exposure to the predator (7 hrs/7 days). In EC mice, predator exposure elevated the level of serotonin (5-Hydroxytrypamine, [5-HT]) in the amygdala as part of the coping response. Subsequently, the serotonin transporter (SERT) and 5-HT1A receptor were up-regulated significantly, but the same did not occur in the 5-HT2C receptor, which is associated with the activation of calmodulin-dependent protein kinase-II (CaMKII) and a transcription factor cAMP response element binding protein (CREB). Our results show that predator exposure induced the activation of CaMKII/CREB, which is accompanied with increased levels of histone acetylation (H3, H4) and decreased histone deacetylases (HDAC1, 2). Subsequently, in the amygdala, the transcription of brain-derived neurotrophic factor (BDNF), neuropeptide Y (NPY) and its Y1 receptor were up-regulated, whereas the Y2 receptor was down-regulated. Therefore, EC facilitated a coping response against a fear associated cue in a PTSD animal model and reduced anxiety by differentially activating serotonergic and NPY-ergic systems.

The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Over the last 50 years, laboratories around the world analyzed the pharmacological effect of Bacopa monniera extract in different dimensions, especially as a nerve tonic and memory enhancer. Studies in animal model evidenced that Bacopa treatment can attenuate dementia and enhances memory. Further, they demonstrate that Bacopa primarily either acts via antioxidant mechanism (i.e., neuroprotection) or alters different neurotransmitters (serotonin (5-hydroxytryptamine, 5-HT), dopamine (DA), acetylcholine (ACh), γ-aminobutyric acid (GABA)) to execute the pharmacological effect. Among them, 5-HT has been shown to fine tune the neural plasticity, which is a substrate for memory formation. This review focuses on the studies which trace the effect of Bacopa treatment on serotonergic system and 5-HT mediated key molecular changes that are associated with memory formation.

Tryptophan hydroxylase (TPH) catalyses l-tryptophan into 5-hydroxy-l-tryptophan, which is the first and rate-limiting step of serotonin (5-HT) biosynthesis. Earlier, we found that TPH2 up-regulated in the hippocampus of postnatal rats after the oral treatment of Bacopa monniera leaf extract containing the active compound bacosides. However, the knowledge about the interactions between bacosides with TPH is limited. In this study, we take advantage of in silico approach to understand the interaction of bacoside-TPH complex using three different docking algorithms such as HexDock, PatchDock and AutoDock. All these three algorithms showed that bacoside A and A3 well fit into the cavity consists of active sites. Further, our analysis revealed that major active compounds bacoside A3 and A interact with different residues of TPH through hydrogen bond. Interestingly, Tyr235, Thr265 and Glu317 are the key residues among them, but none of them are either at tryptophan or BH4 binding region. However, its note worthy to mention that Tyr 235 is a catalytic sensitive residue, Thr265 is present in the flexible loop region and Glu317 is known to interacts with Fe. Interactions with these residues may critically regulate TPH function and thus serotonin synthesis. Our study suggested that the interaction of bacosides (A3/A) with TPH might up-regulate its activity to elevate the biosynthesis of 5-HT, thereby enhances learning and memory formation.

Contextual fear conditioning is a paradigm for investigating cellular mechanisms involved in hippocampus-dependent memory. Earlier, we showed that standardised extract of Bacopa monniera (CDRI-08) improves hippocampus-dependent learning in postnatal rats by elevating the level of serotonin (5-hydroxytryptamine, 5-HT), activate 5-HT3A receptors, and cyclic adenosine monophosphate (cAMP) response element binding (CREB) protein. In this study, we have further examined the molecular mechanism of CDRI-08 in hippocampus-dependent memory and compared to the histone deacetylase (HDACs) inhibitor sodium butyrate (NaB). To assess the hippocampus-dependent memory, wistar rat pups were subjected to contextual fear conditioning (CFC) following daily (postnatal days 15-29) administration of vehicle solution (0.5 % gum acacia + 0.9 % saline)/CDRI-08 (80 mg/kg, p.o.)/NaB (1.2 g/kg in PBS, i.p.). CDRI-08/NaB treated group showed enhanced freezing behavior compared to control group when re-exposed to the same context. Administration of CDRI-08/NaB resulted in activation of extracellular signal-regulated kinase ERK/CREB signaling cascade and up-regulation of p300, Ac-H3 and Ac-H4 levels, and down-regulation of HDACs (1, 2) and protein phosphatases (PP1α, PP2A) in hippocampus following CFC. This would subsequently result in an increased brain-derived neurotrophic factor (Bdnf) (exon IV) mRNA in hippocampus. Altogether, our results indicate that CDRI-08 enhances hippocampus-dependent contextual memory by differentially regulating histone acetylation and protein phosphatases in hippocampus.

In a stressful situation, greater short-nosed fruit bats (Cynopterus sphinx) emit audible vocalization either to warn or to inform conspecifics. We examined the effect of distress calls on bats emitting the call as well as the bats receiving the distress signal through analysis of the hypothalamic-pituitary-adrenal axis and catacholaminargic systems. We measured the levels of neurotransmitters [serotonin (5-HT), dopamine (DA), norepinephrine (NE)] and stress hormones [(adrenocorticotropic hormone (ACTH) and corticosterone (CORT)]. Our results showed that distress call emission elevated the level of ACTH and CORT, as well as 5-HT, DA and NE in the amygdala, for both the call emitting bat and the responding bat. Subsequently, we observed increased activity of glucocorticoid receptor and its steroid receptor co-activator (SRC-1). An expression of SRC-1 was up-regulated in the distress call emitter only, whereas it was at a similar level in both the call responder and silent bats. These findings suggest that bats emitting distress calls and also bats responding to such calls have similar neurotransmitter expression patterns, and may react similarly in response to stress.

Environmental enrichment (EE) has an influential role in reducing behavioral reactivity to stress. We previously observed that EE reduces the anxiety-like behavior in the field mouse Mus booduga accompanied by a reduction in the expression of molecules involved in the stress pathway. In this study, we demonstrate the effect of different housing condition on regulation of micro-RNA-183-SC35-mediated splicing of acetylcholinesterase (AChE). Adult male M. booduga were captured from an agricultural field and housed under nonenriched standard conditions (SC) for 7 days and considered as directly from the wild (DW). On day 8, individuals were randomly assigned to three groups; DW, SC, and EE. The DW group's anxiety-like behavior was assessed in the elevated plus maze (EPM) and open field test (OFT). The SC and EE groups were transferred to their respective conditions and housed for another 30 days. The mice housed in EE showed less anxiety-like behavior on EPM and in OFT compared with DW and SC mice. Interestingly, miR-183 expression was increased following exposure to EPM in EE mice but not in SC mice. Subsequently, the upregulated miR-183 expression suppresses the SC35 expression and shifting of splicing from AChE-S (synaptic) to AChE-R (read-through) form, whereas standard housing condition downregulate miR-183 and induces the splicing of AChE. The upregulated AChE-R form possibly terminates ACh transmission, which is reflected in the level of anxiety-like behavior. Overall, the present study suggests that EE effectively regulates the miR-183 pathway to reduce anxiety-like behavior., (Copyright © 2012 Wiley Periodicals, Inc.)

In the present study, we observed variations in the expression pattern of proteins isolated from the telencephalon of goldfish (Carassius auratus). The expression of a 28 kDa protein was elevated in the individuals trained in a spatial task when compared with the untrained individuals. The ∼28 kDa protein was analyzed using liquid chromatography and mass spectrometry; further, the data were analyzed using the MASCOT search engine. The analysis showed that the ∼28 kDa protein is a β form of 14-3-3 protein with 35.1% identity. In addition, the semiquantitative PCR confirmed the variation in the expression of 14-3-3 between the trained and the untrained groups. Subsequently, we examined the effect of upregulation of 14-3-3 (β) in the neurotransmitters; that is, serotonin (5-hydroxytryptamine, 5-HT) and dopamine (DA). Notably, the level of 5-HT and DA was found to be significantly elevated in the telencephalon of individuals trained in the spatial task than in the untrained individuals. Our results suggest that the spatial learning increases the expression of 14-3-3 (β), which in turn leads to an increase in the level of 5-HT and DA. The upregulated 5-HT and DA may facilitate synapse formation during spatial learning in a novel environment.

In this study, we examined the neuroprotective effect of standardized Bacopa monniera extract (BME: BESEB CDRI-08) against the D-galactose (D-gal)-induced brain aging in rats. Experimental groups were subjected to contextual-associative learning task. We found that the administration of BME in the D-gal-treated group attenuated contextual-associative learning deficits; the individuals showed more correct responses and retrieved the reward with less latency. Subsequent analysis showed that the BME administration significantly decreased advance glycation end product (AGE) in serum and increased the activity of antioxidant response element (ARE) and the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and nuclear transcription factor NF-E2-related factor 2 (Nrf2), accompanied by a reduction in the level of serotonin (5-HT) in the hippocampus. The BME treatment also reversed D-gal-induced brain aging by upregulating the levels of the presynaptic proteins synaptotagmin I (SYT1) and synaptophysin (SYP) and the postsynaptic proteins Ca(2+) /calmodulin dependent protein kinase II (αCaMKII) and postsynaptic density protein-95 (PSD-95) in the hippocampus during synaptic plasticity. A significant finding is that the D-gal- + BME-treated rats exhibited more correct responses in contextual-associative learning than D-gal alone-treated rats. Our findings suggest that BME treatment attenuates D-gal-induced brain aging and regulates the level of antioxidant enzymes, Nrf2 expression, and the level of 5-HT, which was accompanied by concomitantly increased levels of synaptic proteins SYT1, SYP, αCaMKII, p-αCaMKII, and PSD-95., (Copyright © 2012 Wiley Periodicals, Inc.)

Bacosides, the effective component of standardised leaf extract of Bacopa monniera (BESEB CDRI-08) has been reported to have memory enhancing effect. Our previous reports suggested that BESEB CDRI-08 (BME) improves memory in postnatal rats by enhancing serotonin [5-hydroxytryptamine (5-HT)] metabolism, its transportation and subsequently activates 5-HT(3A) receptor during hippocampus-dependent learning. In this study, we examine whether the up-regulated 5-HT(3A) receptor activity by BME modulate microRNA 124-CREB pathway to enhance synaptic plasticity. Wistar rat pups received single dose of vehicle solution (0.5 % gum acacia + 0.9 % saline)/BME (80 mg/kg)/mCPBG (10 mg/kg)/BME + mCPBG during the postnatal days (PND) 15-29. On PND 30, individuals were trained at brightness discrimination task and 24 h later, they were tested on the task. The BME treated group exhibited significantly lower percentage of errors during retention than acquisition. In addition, pre-miR-124 expression in hippocampus was significantly down-regulated in the BME and mCPBG + BME treated groups combined with a significant increase in the plasticity related genes, cAMP response element-binding protein, its phosphorylation and postsynaptic density protein 95. Our results suggest that this may be one of the mechanisms of bacosides present in BME for the memory enhancement.