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© 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Pilocarpine is a selective M1/M3 agonist of muscarinic acetylcholine receptor subtypes. Muscarinic acetylcholine receptors are G protein-coupled receptors. These receptors are different drug targets. The aim of the present work was to investigate the effect of pilocarpine on the expression of M3 muscarinic acetylcholine receptor, the AChE activity, IL-8 release response, and proliferation in K562 cells, via muscarinic receptor activation. Human chronic myeloid leukemic cell cultures were incubated with drugs. Proliferation assays were performed by BrdU assay. Expression of M3 muscarinic acetylcholine receptor and apoptosis proteins such as bcl, bax, cyt C, and caspases was assessed with the semiquantitative Western blotting method. Pilocarpine inhibits chronic myeloid cell proliferation and M3 muscarinic acetylcholine receptor protein expression. Pilocarpine increases caspase-8 and -9 expression levels, upregulating the proapoptotic protein Bax and downregulating the expression levels of the antiapoptotic protein Bcl-2. The apoptotic activity of pilocarpine is associated with an increase in AChE activity. M3 muscarinic acetylcholine receptors can activate multiple signal transduction systems and mediate inhibitory effects on chronic myeloid K562 cell proliferation depending on the presence of 1% FBS conditions. This apoptotic effect of pilocarpine may be due to the concentration of pilocarpine and the increase in AChE level. Our results suggest that inhibition of cell proliferation by inducing apoptosis of pilocarpine in K562 cells may be one of the targets. M3 selective agonist may have therapeutic potential in chronic myeloid leukemia. Graphical Abstract: [Figure not available: see fulltext.].

The results we obtained from this study gave information about the determination of alpha 7 nicotinic acetylcholine receptor (α7-nACh) expression in human erythroleukemia cells, as well as whether it has a role in calcium release and cell proliferation in the presence of nicotinic agonist, antagonists. Determining the roles of α7 nicotinic receptors in erythroleukemia cells will also contribute to leukemia-related signal transduction studies. This study is primarily to determine the role of nicotinic agonists and antagonists in cell proliferation, α7 nicotinic acetylcholine receptor expression, and calcium release. The aim of this study, which is a continuation and an important part of our previous studies on the cholinergic system, has contributed to the literature on the human erythroleukemia cell signaling mechanism. Cell viability was evaluated by the trypan blue exclusion test and Bromodeoxyuridine/5-Bromo-2'-deoxyuridine (BrdU) labeling. Acetylcholine, nicotinic alpha 7 receptor antagonist methyllycaconitine citrate, and cholinergic antagonist atropine were used to determine the role of α7-nACh in K562 cell proliferation. In our experiments, the fluorescence spectrophotometer was used in Ca2+ measurements. The expression of nicotinic alpha 7 receptor was evaluated by western blot. The stimulating effect of acetylcholine in K562 cell proliferation was reversed by both the α7 nicotinic antagonist methyllycaconitine citrate and the cholinergic antagonist, atropine. Methyllycaconitine citrate inhibited K562 cell proliferation partially explained the roles of nicotinic receptors in signal transduction. While ACh caused an increase in intracellular Ca2+, methyllycaconitine citrate decreased intracellular Ca2+ level in K562 cell. The effects of nicotinic agonists and/or antagonists on erythroleukemic cells on proliferation, calcium level contributed to the interaction of nicotinic receptors with different signaling pathways. Proliferation mechanisms in erythroleukemic cells are under the control of the α7 nicotinic acetylcholine receptor via calcium influx and different signalling pathway.

OBJECTIVE: Mechanisms contributing to the post-traumatic stress disorder (PTSD) that involve several physiological sys- tems, and the activation of the hypothalamic-pituitary-adrenal axis (HPA) is one of the most known systems in the PTSD pathophysiology. The present study investigates the potential effects of methylprednisolone, metyrapone and their association with the noradrenergic system within the rostral pons, a region containing the locus coeruleus (LC) in a rat model of PTSD induced with predator scent. METHODS: In this study, Sprague-Dawley rats were exposed to the stress by exposure to the scent of dirty cat litter, which is a natural stressor of a predator. One week later, the rats were re-exposed to a situational reminder (clean cat litter). The rats were treated using either methylprednisolone, metyrapone or physiological saline before exposure to a situational reminder (n=8 in each group). Noradrenaline (NA) levels in the rostral pons homogenates were analysed using ELISA. RESULTS: The anxiety indices of the rats exposed to the trauma were found to be significantly higher than the anxiety indices of the control rats. Metyrapone produced a significant increase in the anxiety indices of the non-stressed rats, and methylprednisolone did not produce a change in the anxiety indices of the non-stressed rats. Methylprednisolone treatment suppressed the anxiety in the stressed rats. Metyrapone treatment increased the anxiety indices in the stressed rats but still being lower than that of the saline-treated stressed rats. Significant decrease in the freezing time was observed following the methylprednisolone treatment both in the stressed and non-stressed rats. NA content in the rostral pons of the stressed rats was significantly higher than that of the non-stressed rats. Methylprednisolone or metyrapone treatments decreased the NA content in the non-stressed rats as compared to the saline treatment. However, these decreases were not significant. CONCLUSION: In this study, findings suggest that stress may give rise to endocrine, autonomic and behavioural responses. The anxiety indices and NA levels in the rostral pons increased with the traumatic event. The methylprednisolone treatment may suppress anxiety through interactions between the LC and the HPA axis.

Treatment of fasted mice and rats with the nonselective muscarinic antagonist, scopolamine or atropine, causes convulsions after food intake. This study evaluated the effect of fasting on the expression of M1 and M2 muscarinic receptors in the brain regions, the relationship between receptor expression and seizure stages, and the muscarinic receptor subtype which plays a role in the occurrence of convulsions. Mice were grouped as allowed to eat ad lib (fed) and deprived of food for 24h (fasted). Fasted animals developed convulsions after being treated with scopolamine (60%) or the selective M1 receptor antagonist pirenzepine (10mg/kg; 20% and 60mg/kg; 70%) and given food. Fasting increased expression of M1 receptors in the frontal cortex and M2 receptors in the hippocampus, but produced no change in the expression of both receptors in the amygdaloid complex. Food intake after fasting decreased M1 receptor expression in the frontal cortex and M1 and M2 receptor expression in the hippocampus. Seizure severity was uncorrelated with muscarinic receptor expression in the brain regions. Taken together, these findings provide evidence for the role of M1 muscarinic receptor antagonism and fasting-induced increases in M1 and M2 expression possible underlying mechanism in the occurrence of convulsions in fasted animals.

Objective The timing of administration of pharmacologic agents is crucial in traumatic stress since they can either potentiate the original fear memory or may cause fear extinction depending on the phase of fear conditioning. Brain noradrenergic system has a role in fear conditioning. Data regarding the role of prazosin in traumatic stress are controversial. Methods In this study, we examined the effects of prazosin and the noradrenergic system in fear conditioning in a predator stress rat model. We evaluated the direct or indirect effects of stress and prazosin on noradrenaline (NA), gamma-aminobuytyric acid (GABA), glutamate, glycine levels and choline esterase activity in the amygdaloid complex, the dorsal hippocampus, the prefrontal cortex and the rostral pons. Results Our results demonstrated that prazosin might alleviate defensive behaviors and traumatic stress symptoms when given during the traumatic cue presentation in the stressed rats. However prazosin administration resulted in higher anxiety levels in non stressed rats when the neutral cue was presented. Conclusion Prazosin should be used in PTSD with caution because prazosin might exacerbate anxiety in non-traumatized subjects. However prazosin might as well alleviate stress responses very effectively. Stress induced changes included increased NA and GABA levels in the amygdaloid complex in our study, attributing noradrenaline a possible inhibitory role on fear acquisition. Acetylcholine also has a role in memory modulation in the brain. We also demonstrated increased choline esterase acitivity. Cholinergic modulation might be another target for indirect prazosin action which needs to be further studied.

Background: Muscarinic receptors have many functions in the cells and tissues. Acetylcholine (ACh) plays an important role in cellular physiology. ACh also acts at the different parts of the centra...

Amaç: Muskarinik reseptörler merkezi sinir sistemindeasetilkolinin çeşitli etkilerine aracılık ettiği gibi, parasempatik sinirsistemi ile etkileşen sinirsel olmayan dokulara da aracılık ederler.Çalışmamızda, M3 muskarinik reseptör alttipinin K562 kanserhücre çoğalması ve ölümündeki rolünü belirlemeye çalıştık.Gereçler ve Yöntemler: Hücre çoğalması bromodeoksiüridin(BrDU) yöntemi ile belirlenmiştir. Hücre ölümü, erken ve geçapoptoz Anneksin V ve propidyum iodid (PI) varlığında akışsitometrisi yöntemi ile gösterilmiştir. Nuklear dış sinyal düzenleyicikinaz (ERK/fosfo-ERK) ekspresyonu western emdirimi yöntemiile belirlenmiştir.Bulgular: Çalışmamızda 48 saat karbakol(CCh) ile muameleedilen K562 hücre sayısında azalma belirlenmiştir. Hücreler24 saat CCh ile muamele edildiklerinde erken apoptotik hücresayısında azalma gözlemlenirken geç apoptoz ve nekrotik hücresayısında değişim olmamıştır. Bununla birlikte, 48 saat boyuncaCCh ile muamele olan hücrelerde, erken ve geç apoptotik hücresayısı azalırken, nekrotik hücrelerin sayısı artmıştır. CCh ilemuamele edilen hücrelerde nüklear ERK ekspresyonu artarkenbu etki 1,1-dimetil-4-difenilasetoksipiperidinium iodid (4DAMP)ile geri çevrilmiştir. Aynı koşullarda CCh ile muamele edilenhücrelerde nuklear pERK ekspresyonu azalmış, bu etki 4DAMPile geri çevrilmemiştir.Sonuç: Bulgularımız, K562 hücre proliferasyonundakikolinerjik etkinin yalnızca muskarinik mekanizma ile değildiğer kolinerjik reseptörlerin de katkısıyla gerçekleştiğinidüşündürmektedir., Objectives: Muscarinic receptors mediate diverse actions ofacetylcholine in the central nervous system and in non-nervoustissues innervated by the parasympathetic nervous system.Our study aims to evaluate the potential association of theM3 muscarinic receptor with K562 cell proliferation and death.Materials and Methods: Cell proliferation was evaluatedby bromodeoxyuridine (BrDU) incorporation. To show early,late apoptosis and cell death, cells were labelled with AnnexinV, propidium iodide (PI) and analyzed by flow cytometry. Nuclearextracellular signal-regulated kinase (ERK/pERK) expressionwas measured by western blot analysis.Results: Treatment with carbachol (CCh) for 48h decreased cellnumber. Exposing K562 cells to CCh for 24h decreased the number ofearly apoptotic cells but did not change the number of late apoptotic andnecrotic cells. CCh treatment for 48h increased the number of necroticcells, but decreased the number of early and late apoptotic cells. Inresponse to CCh, nuclear ERK expression was increased and this effectwas reversed by 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide(4DAMP). Nuclear pERK expression was decreased in CCh treatedcells, 4DAMP did not reverse the effect.Conclusion: Our data suggest that cholinergic agonist CChaffects cell proliferation in K562 cells not only through muscarinicreceptors but also through other cholinergic receptors.

Objective: The purpose of this study was to investigate ifstimulating auto-paracrine muscarinic receptor signalling pathwaycould change human erythroleukemia K562 cell proliferation andcaspase 3, 8 and 9 expression levels. To better understand the role ofmuscarinic receptors in cell signalling mechanism, we investigatedthe effects of several compounds on human erythroleukemiaK562 cell proliferation and caspase 3, 8 and 9 expression. Thesecompounds were M3 muscarinic receptor agonist, pilocarpine, proinflammatorycytokine, tumor necrosis factor (TNF)-alpha, andthe wortmannin which is a phosphoinositide 3-kinase inhibitor.Materials and Methods: Cell proliferation and cell viabilitywere evaluated by the trypan blue exclusion test and 5-Bromo-2-deoxy-uridine (BrdU) Labelling and Detection Kits. Caspase 3, 8and 9 expression levels were determined by immunoblot analysis.Results: Both pilocarpine and TNF-alpha caused a small increasein human erythroleukemia K562 cell proliferation. However, whenall the compounds were treated together, proliferation of humanerythroleukemia K562 cells increased significantly when compared tountreated control cells. TNF-alpha and wortmannin treatment increasedcaspase 3 and caspase 8 expression patterns significantly in humanerythroleukemia K562 cells. TNF-alpha and wortmannin treatmentincreased caspase 9 expression level (P>0.05) but it was not significant.Conclusion: These findings partly demonstrated that M3muscarinic receptor mediated an increase in K562 cell proliferation.Pilocarpine prevented TNF-alpha and wortmannin inducedcaspase 3 and 8 expression and indirectly showed apoptosis inhuman erythroleukemia K562 cells., Amaç: Bu çalışmanın amacı, otoparakrin M3 muskarinikreseptör sinyal yolağının uyarılmasının, insan eritrolösemi K562hücrelerinin çoğalmasında ve kaspaz 3, 8 ve 9 ekspresyon seviyeleriüzerinde etkisi olup olmadığını araştırmaktır. Hücre sinyalileti mekanizmasında muskarinik reseptörlerin rolünü daha iyianlamak üzere, çeşitli bileşiklerin insan eritrolösemisi K562 hücreproliferasyonu ve kaspaz 3, 8 ve 9 ekspresyon seviyeleri üzerindekietkilerini araştırdık. Bu bileşikler, M3 muskarinik reseptör agonisti,pilokarpin, pro-enflamatuvar sitokin, tümör nekroz faktör (TNF)-alfa ve fosfoinositid 3-kinaz inhibitörü wortmanindir.Gereçler ve Yöntemler: Hücre çoğalması ve hücre canlılığı,tripan mavisi testi ve 5-Bromo-2-deoxy-uridine (BrdU) İşaretlemeve Belirleme kitleri ile değerlendirildi. Kaspaz 3, 8 ve 9 ekspresyonseviyeleri immunoblot analizi ile belirlendi.Bulgular: Hem pilokarpin, hem de TNF-alfa, insan eritrolösemiK562 hücre çoğalmasında çok az artışa neden oldu. Ancak, tümbileşikler birlikte muamele edildiğinde, insan eritrolösemi K562hücrelerinin çoğalması, muamele edilmeyen kontrol hücrelerinegöre anlamlı olarak arttı. TNF-alfa ve wortmanin ile muameleedilen K562 hücrelerinde kaspaz 3 ve kaspaz 8 ekspresyonuseviyelerinde anlamlı değişim belirlendi. TNF-alfa ve wortmanninmuamelesi kaspaz 9 ekspresyon seviyesini arttırdı (P> 0.05) ancakanlamlı değildi.Sonuç: Bu bulgular, kısmen M3 muskarinik reseptör aracılıK562 hücre çoğalmasında artış olduğunu göstermektedir.Pilokarpin, insan eritrolösemi K562 hücrelerinde, TNF-alfa vewortmanin ile uyarılan kaspaz 3 ve 8 ekspresyonunu önledi vedolaylı olarak apoptozu gösterdi.

Objective: The B-cell lymphoma/leukemia-2 (Bcl-2) family of proteins governs mitochondrial membrane permeability where the programmed apoptotic process is controlled by the balance between proapoptotic (Bax) and antiapoptotic (Bcl-2) proteins. We aimed to investigate the [Bcl-2]/[Bax] in different brain regions in a post-traumatic stress disorder rat model. Methods: Female Sprague-Dawley rats were exposed to dirty cat litter (trauma) for 10 min and the protocol was repeated 1 week later with a trauma reminder (clean litter) in reversed 12 h light/dark cycle. The rats received intraperitoneal saline, fluoxetine (2.5 mg/kg/day) or propranolol (10 mg/kg/day) for 7 days between exposure sessions. Following exposure to the trauma reminder, elevated plus maze experiments were done. Immunoblotting was used to quantify [Bcl-2] and [Bax] proteins in the homogenates of the dorsal hippocampus, the frontal cortex and the amygdaloid complex. Results: Fluoxetine reversed the increases in the anxiety indices and the freezing times. In the amygdaloid complex and the frontal cortex, the [Bcl-2]/[Bax] decreased in the traumatized control rats significantly (p

Treatment of fasted mice and rats with the nonselective muscarinic antagonist, scopolamine or atropine, causes convulsions after food intake. This study evaluated the effect of fasting on the expression of M

Background: Many studies suggested that Acetylcholine (ACh) might serve as an autocrine/ paracrine growth factor in several types of tumors or tumor cell lines. High levels of Acetylcholinesterase (AChE) activity have been reported in primary brain tumors, ovarian, colon and lung tumors. Objectives: The role of cholinergic signaling needs to be clarified in in leukemia. Method: K562 cells were derived from a chronic myelogenous leukemia patient during blast crisis serving as pluripotent hematopoietic stem cells. K562 cells were incubated with various cholinergic agonists or antagonists to investigate the role of ACh in different differentiated cell lines. Results: Our experiments showed that AChE activity was increased in response to ACh in undifferentiated K562 cells, but in the erythroid differentiated K562 cells a high concentration of ACh (1 mM) decreased the AChE activity. ACh failed to elevate the AChE activity in the megakaryocytic differentiated K562 cells. An AChE inhibitor, eserine, also suppressed the AChE activity in a concentration-dependent manner. Choline uptake inhibition by hemicholinium did increase the AChE activity but not in the erythroid differentiated K562 cell line. Likewise, megakaryocytic differentiated K562 cells also displayed a similar pattern. Vesamicole, a vesicular choline uptake inhibitor, produced similar results. Curare, a nicotinic antagonist, elevated the cell counts of the megakaryocytic differentiated cells. Conclusion: Our findings may suggest excess extracellular ACh will decrease the cell growth in undifferentiated and megakaryocytic differentiated K562 cell lines through nicotinic type cholinoceptors.

Programlanmış hücre ölümü olan apoptoz birçok fizyolojik süreçte aktif rol oynamaktadır. Apoptozun, büyüme faktörlerinin eksikliği, DNA hasarı ve birden fazla faktörü içeren çeşitli hücresel stresle aktive olan ‘hücre içi’ ve ölüm reseptörlerine ligandın bağlanmasıyla kaspazların aktive olduğu ‘hücre dışı’ olmak üzere iki yolağı vardır. Apoptotik hücre sayısı ile organizmanın sağlıklı olup olmadığı belirlenir. Apoptoz oranının azalması hücre sayısını arttırırken, apoptoz oranının artması hücre sayısını azaltarak dokularda tahribata neden olmaktadır. Apoptotik sinyallemede düzensizlik çeşitli hastalıklarda/bozukluklarda primer ya da sekonder rol oynamaktadır. Son yıllarda apoptozun nörodejeneratif hastalıklarla ilgili çalışmaları ön plana çıkmaya başlamıştır. Apoptotik sinyal yolaklarının daha iyi tanımlanması, pro- ve anti-apoptotik genlerin belirlenmesiyle, çalışmalar hız kazanmıştır. Travma Sonrası Stres Bozukluğu gibi nörodejeneratif bozukluklarda beyindeki yapısal ve fonksiyonel değişiklikler mitokondriyal stres ile ilişkilidir. Fizyolojik koşullarda hayati öneme sahip olan apoptoz, patolojik koşullarda mekanizmanın tetiklenmesine ve kontrolsüz hücre çoğalmasına yol açmaktadır. Hücre ölümünü engelleyen terapötik ilaçların geliştirilmesiyle apoptoz aracılı nörodejenaratif bozuklukların tedavisine yeni umutlar oluşacaktır., Apoptosis is programmed cell death, which actively occurs in many physiological processes. It can be triggered in two ways: (i) defects in growth factor, DNA damage, and other many factors that can cause cellular stress, which is an intracellular pathway, and (ii) ligand binding to death receptors and activation of caspases. The apoptotic cell count can be determined by the health of the whole organism. A higher apoptotic ratio can indicate a decrease in the number of cells and tissue damage, while a lower apoptotic ratio can indicate an increase in the number of cells. Irregularity in apoptotic signals can play primary or secondary roles in various diseases/disorders. Research on apoptosis depends on neurodegeneration has been initiated in the past few years. Definition of apoptotic signal pathways and apoptotic regulation and determination of pro- and anti-apoptotic genes are the main topics that have accelerated research on apoptosis. Neurodegenerative disorders such as post-traumatic stress disorder neuronal damage associated with changes in brain structure and function may be related to the mitochondrial stresses. In physiological conditions, apoptosis is crucial for the organism, while in pathological conditions, apoptosis can cause uncontrolled cell division. Development of therapeutic medicine that inhibits the cell death may be the new choice of treatment for neurodegenerative diseases/disorders.

Hypertension is a multifactorial disorder that constitutes a major risk factor for the cardiovascular system. Heterotrimeric G-proteins, which couple receptors for diverse extracellular enzymes or ion channels, are correlated with disease mechanisms. Several studies have demonstrated an association between G protein polymorphisms and essential hypertension in some populations, although contradictive results also exist. In this study, we have investigated the potential role of the C825T, C1429T, and G5177A polymorphisms of the β3 subunit of G-proteins in essential hypertension in a group of Turkish subjects. Genomic DNA from 106 normotensive individuals (117.4 ± 13.1, 75.2 ± 10.5; systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels, respectively) and 101 hypertensive subjects (152.3 ± 18.0, 92.5 ± 11.6; SBP and DBP levels, respectively) were studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing methods for these polymorphisms. Allele frequencies of the polymorphisms were consistent with Hardy Weinberg equilibrium, except for the C825T polymorphism (χ(2) = 7.8). The frequencies of the 825T and 1429T variants were higher in hypertensive subjects compared to those of controls. Differences between hypertensives and controls were not statistically significant, though difference was very close to significance for C825T (p = 0.056 and 0.099 for 825T and 1429T, respectively). T allele frequency in overall population showed significant association with hypertension for C825T (0.0134). The prevalence of the 5177A-variant was very low and all subjects carrying it were heterozygotes in both groups.

Muscarinic receptors mediate a variety of cellular responses to acetylcholine, including inhibition of adenylate cyclase, breakdown of phosphoinositide and modulation of ion channels. These receptors are relatively abundant in the central nervous system and peripheral parasympathetic nervous system. Many cells express a mixture of muscarinic receptor transcripts. Changes in muscarinic M(2) and M(3) receptor mRNA levels in response to agonist treatment have been reported in cerebellar granule cells, Chinese hamster ovary cells, lymphocytes and in the human neuroblastoma cell line SH-SY5Y.In this study, we investigated the effects of agonist stimulation on cell proliferation and on the levels of muscarinic receptor expression in K562 chronic myelogenous leukemia cells.Total RNA and crude membrane fractions were prepared from K562 cells challenged with carbachol (CCh). Muscarinic receptor subtype expression was determined by RT-PCR and western blot analysis. Proliferation and cell viability were evaluated by the trypan blue exclusion test and BrDU labeling.We showed that CCh-treatment leads to changes in muscarinic M(2), M(3), and M(4) receptor transcripts as well as M(2) and M(3) protein levels. We also found that CCh decreased proliferation of K562 cells in a time dependent manner, an effect prevented by atropine. These results suggest that CCh modulates K562 chronic myelogenous leukemic cells proliferation through muscarinic acetylcholine receptors.

Aim: The identity of muscarinic acetylcholine receptors (mAchR) involved in cholinergic-mediated contraction of the guinea pig gallbladder has been a matter of debate. Different groups have suggested the involvement of M1, M2, M3, or M4 receptor subtypes in the contraction of this tissue. The objective of this study was to identify the mAchR subtypes expressed in the guinea pig gallbladder by RT-PCR. Methods: Total RNA prepared from frozen guinea pig gallbladder tissue was amplified by using specific primers for the M1–M4 receptor subtypes. Results: M2, M3, and M4 transcripts were detected in the following rank order: M4 > M2 > M3. We were unable to demonstrate the expression of the M1 receptor subtype in this tissue. Conclusions: Our results are in agreement with our previous binding and functional data.

d -cycloserine (DCS), an FDA approved anti-tuberculosis drug has extensively been studied for its cognitive enhancer effects in psychiatric disorders. DCS may enhance the effects of fear extinction trainings in animals during exposure therapy and hence we investigated the effects of DCS on distinct behavioral parameters in a predator odor stress model and tested the optimal duration for repeated daily administrations of the agent. Cat fur odor blocks were used to produce stress and avoidance and risk assessment behavioral parameters were used where DCS or saline were used as treatments in adjunct to extinction trainings. We observed that DCS facilitated extinction training by providing further extinction of avoidance responses, risk assessment behaviors and increased the contact with the cue in a setting where DCS was administered before extinction trainings for 3 days without producing a significant tolerance. In amygdala and hippocampus, GluN1 protein expressions decreased 72 h after the fear conditioning in the traumatic stress group suggesting a possible down-regulation of NMDARs. We observed that extinction learning increased GluN1 proteins both in the amygdaloid complex and the dorsal hippocampus of the rats receiving extinction training or extinction training with DCS. Our findings also indicate that DCS with extinction training increased GluN1 protein levels in the frontal cortex. We may suggest that action of DCS relies on enhancement of the consolidation of fear extinction in the frontal cortex.

The present study aimed to determine the effect of two M 2 /M 4 -selective muscarinic receptor antagonists on blocking the hydrolysis of carbachol (CCh) stimulated phospho-inositide (PI) breakdown in order to address the possibility that a muscarinic receptor other than the M 3 receptor is involved in PI hydrolysis in this tissue. Gallbladder tissue slices labeled with myo-[2- 3 H] inositol were incubated with increasing concentrations of antagonists and agonist. After the reactions were terminated by the addition of chloroform/methanol, labeled inositol phosphates were separated using anion exchange chromatography. Muscarinic M 2 antagonists methoctramine and gallamine both inhibited carbachol-induced PI breakdown at high concentrations, with log IC 50 values of − 5.145 and − 6.049, respectively. Gallamine at 10 − 5 M concentration failed to displace the dose-response curve for carbachol-induced accumulation of inositol triphosphate (IP 3 ). Our data suggest that M 3 receptors play a major role in stimulation of PI hydrolysis in the guinea-pig gallbladder.

The dysregulation of hypothalamic–pituitary–adrenal axis and noradrenergic, serotonergic and glutamatergic systems are thought to be involved in the pathophysiology of post-traumatic stress disorder. The effect of selective M1 muscarinic receptor antagonist, pirenzepine on anxiety indices was investigated by using elevated plus maze, following exposure to trauma reminder. Upon receiving the approval of ethics committee, Sprague–Dawley rats were exposed to dirty cat litter (trauma) for 10 min and 1 week later, the rats confronted to a trauma reminder (clean litter). The rats also received intraperitoneal pirenzepine (1 or 2 mg/kg/day) or saline for 8 days. Noradrenaline (NA) concentration in the rostral pons was analyzed by HPLC with electrochemical detection. The anxiety indices of the rats subjected to the trauma reminder were increased when compared to control rats (p

Muscarinic acetylcholine receptors (mAChRs) are members of the superfamily of G protein coupled receptors (GPCRs). Muscarinic receptors are relatively abundant in the central nervous system and in the peripheral parasympathetic nervous system. Several studies have suggested that muscarinic receptors also mediate some cellular events in hematopoietic cells. K562 erythroleukemia cells contain muscarinic receptors M2, M3 and M4, and activation of muscarinic receptors changes cell proliferation. We examined the effects of several compounds on cell proliferation in K562 erythroleukemia cells. These included a muscarinic receptor agonist carbachol (CCh), a protein kinase inhibitor staurosporine; the phospholipase C inhibitor U73122, the MEK 1-2 inhibitor UO126, the PI3-kinase inhibitor wortmannin, the Ca(2+) chelators BAPTA/AM and 2-aminoethoxy-diphenylborate (2APB). In addition, we also investigated muscarinic receptor mediated protein kinase C (PKC) expression in K562 cells. CCh caused a decrease in DNA synthesis in K562 cells supplemented with 1% fetal bovine serum after starvation. Pre-treatment of K562 cells with U73122 and BAPTA/AM antagonized the inhibitory effect of CCh, suggesting that phospholipase C and intracellular calcium are involved in CCh-mediated inhibition of proliferation in K562 cells. Our data also suggest that the regulatory roles of protein kinase C and the MAPK/ERK pathways in K562 cell proliferation are independent of cholinergic activation.

Objectives: Muscarinic acetylcholine receptors (mAChR) belong to a family of G protein coupled receptors (GPCRs). These mAChRs regulate several important physiological functions by activating a wide variety of cellular signaling pathways. We have previously shown that muscarinic acetylcholine (M-2, M-3 and M-4) receptors are expressed in K562 cells. In this study, we investigated the effect of muscarinic agonist, antagonists and different signaling pathway inhibitors on c-Fos and cyclin D-1 transcripts, using reverse transcriptase polymerase chain reaction (RT-PCR) that allows changes of very rare transcripts to be monitored. Material and Methods: Total RNA was prepared from K562 cells challenged with muscarinic agonist, antagonists and inhibitors. c-Fos and cyclin D-1 expression were determined by RT-PCR. Results: We showed that treatment with muscarinic agonist, antagonists and inhibitors leads to changes in c-Fos and cyclin D-1 expression in K562 cells. Conclusions: Our results suggest that muscarinic receptors regulate expression of c-Fos and cyclin D-1 genes in K562 cells via different signaling pathways.

Amac: Post travmatik stres bozuklugunda (PTSD) iyonotropik glutamat reseptor (GluN1)’lerinin (GluN1) ve kalmodulinin birlikte etki ederek nitrik asit sentaz (NOS) aktivasyonu yaptigi bilinmemektedir.Gerec ve Yontem: Her iki cinsiyetten Sprague-Dawley sicanlari kirli kedi kumuyla saldirgan hayvan kokusuna maruz birakildiktan sonra, sicanlara yukseltilmis t labirenti deneyleri uygulanmistir. Deney sonrasi sicanlarin anksiyete endeksleri hesaplanmis ve kalmodulin, NOS ve GluN1 olcumleri icin hipokampus ve amigdala doku ornekleri Western Blot yontemi icin hazirlanmistir.Bulgular: Travmatize edilen sicanlarin anksiyete indeksleri kontrol grubuna gore anlamli olarak yuksek bulunmustur (p < 0.05). Dorsal hipokampus ve amygdaloid komplekste travmatize sicanlarin GluN1 ve kalmodulin duzeyleri azalmistir. NOS ekspresyonu her iki bolgede artis gostermesine karsin, amigdaloid kompleksteki artis (p < 0.001) dorsal hipokampuse gore (p < 0.05) istatiksel olarak daha anlamli bulunmustur.Sonuc: Saldirgan hayvan kokusu maruziyeti sicanlarda, PTSD semptomlari ve eksitotoksisite ile iliskili beyin alanlarinda nNOS ekspresyonunda artma ve GluN1 reseptorlerinde azalma ile birlikte uzun sure devam eden anksiyete iliskili etkilere neden olmaktadir. Sonuclarimiz, NOS aktivitesinin GluN1 disindaki nedenlerle arttigini gostermektedir

This study shows the possible contribution of muscarinic receptors in the pathophysiology of post-traumatic stress disorder. Sprague-Dawley rats of both sexes were exposed to dirty cat litter (trauma) for 10 min and the protocol was repeated 1 week later with a trauma reminder (clean litter). The rats also received intraperitoneal fluoxetine (2.5, 5 or 10 mg/kg/day), propranolol (10 mg/kg/day) or saline for 7 days between two exposure sessions. Functional behavioral experiments were performed using elevated plus maze, following exposure to trauma reminder. Western blot analyses for M 1 , M 2 , M 3 , M 4 and M 5 receptor proteins were employed in the homogenates of the hippocampus, the frontal cortex and the amygdaloid complex. The anxiety indices increased from 0.63 ± 0.02 to 0.89 ± 0.04 in rats exposed to the trauma reminder. The freezing times were also recorded as 47 ± 6 and 133 ± 12 s, in control and test animals respectively. Fluoxetine or propranolol treatments restored the increases in the anxiety indices and the freezing times. Female rats had higher anxiety indices compared to males. Western blot data showed increases in M 2 and M 5 expression in the frontal cortex. Expression of M 1 receptors increased and M 4 subtype decreased in the hippocampus. In the amygdaloid complex of rats, we also detected a down-regulation of M 4 receptors. Fluoxetine and propranolol only corrected the changes occurred in the frontal cortex. These results may imply that muscarinic receptors are involved in this experimental model of post-traumatic stress disorder.

Dopamine has been shown to influence blood pressure by regulating renal sodium excretion through direct interaction with the dopamine receptors, especially with the Dopamine D1 receptor (DRD1). To better understand the role of polymorphisms in those effects, we investigated the association between two polymorphic sites in the DRD1 promoter region (A-48G, G-94A) and essential hypertension in the Turkish population. The DRD1 variants were genotyped by restriction fragment length polymorphism (RFLP) analysis. A total of 205 unrelated individuals were enrolled in the study. We found that genotype distributions and allele frequencies of the control and hypertensive subjects were very similar and did not show any significant difference with respect to blood pressure (BP) and hypertension. Contribution of the gene variances in BP or hypertension by sex differences and dependence on body mass index (BMI) were also evaluated. Distribution of genotypes and allele frequencies were found to be in line with previous reports. However, increments detected in hypertensive subjects were far from being statistically significant.

1 In the present study we have investigated the expression of muscarinic receptors in K562 erythroleukaemic cells and the effects of muscarinic agonist and antagonists on extracellular citrulline levels in these cells, as a marker of nitric oxide (NO) generation. 2 Muscarinic acetylcholine receptors (M(1)-M(5)) play key roles in regulating many diverse physiological processes. Recent studies suggest that muscarinic receptors mediate some cellular events in haematopoietic cells. Multiple subtypes of muscarinic receptors are expressed in different human cells. NO, a free radical and a signaling molecule, is involved in the regulation of many physiological functions and derived from certain nitric oxide synthases (NOS), which are related to muscarinic receptors. 3 In this study, the presence of M(2), M(3) and M(4) subtypes in K562, an erythroleukaemic cell line, was demonstrated by using the reverse transcriptase-polymerase chain reaction. Moreover, the generation of NO induced by carbachol, a non-selective muscarinic agonist, was investigated by using high-performance liquid chromatography to measure changes in extracellular l-citrulline levels. 4 We found that carbachol enhanced l-citrulline production in K562 erythroleukaemic cells. The effect of carbachol on l-citrulline production was antagonized by atropine and 4-diphenylacetoxy-N-methylpiperidine (4-DAMP), while tropicamide had little effect. These results suggest that the muscarinic receptor M(3) subtype may mediate NO signaling in K562 erythroleukaemic cells.

1. The affinities of 10 selective muscarinic receptor antagonists against [3H]-quinuclidinyl benzilate (QNB) binding were determined to characterize the muscarinic receptors present in guinea-pig gallbladder smooth muscle. The highest correlation was obtained for the comparison between the pKi values for the gallbladder smooth muscle and M2 sites. Pirenzepine revealed two binding sites with affinities indicating the presence of muscarinic M2 receptors in abundance and a minor population of an additional site(s). 2. Carbachol produced gallbladder contractions, stimulated phosphoinositide (PI) hydrolysis and inhibited cAMP formation concentration-dependently with pD2 values of 6.12 +/- 0.11, 5.18 +/- 0.33 and 7.19 +/- 0.15, respectively. 3. Pirenzepine, 4-DAMP, HHSiD, pF-HHSiD, AF-DX 116, methoctramine, AQ-RA 741, guanylpirenzepine and AF-DX 384 showed competitive antagonism against carbachol-induced gallbladder contractions. There was no correlation between the pA2 values for the gallbladder and pKi values for the M2 sites, whereas significant correlations were found for the M1, M3 and M4 sites, the best correlation being between the pA2 values for the gallbladder and M4 subtypes. 4. Finally, the presence of both m2 and m4 receptor proteins were demonstrated by Western blot analysis. It is concluded that guinea-pig gallbladder smooth muscle has both muscarinic M2 and M4 receptors, which are coupled to adenylate cyclase inhibition and PI hydrolysis. 5. Although it seems likely that M2 receptors do not play a primary role in carbachol-induced guinea-pig gallbladder contraction, the characterization of the muscarinic subtypes which mediate these contractile responses needs further evidence.