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The central autonomic network, which is connected to the limbic system structures including the amygdala (AMY) and anterior hippocampus (aHIP), regulates the sympathetic and parasympathetic modulation of visceromotor, neuroendocrine, pain, and behavior manifestations during stress responses. Heart rate variability (HRV) is useful to estimate the cardiac autonomic tone. The levels of phosphorylation on the Ser831 and Ser845 sites of the GluA1 subunit of the AMPAr (P-GluA1-Ser845 and P-GluA1-Ser831) are useful markers of synaptic plasticity. The relation between synaptic plasticity in the human limbic system structures and autonomic regulation in humans is unknown. This study investigated the association between HRV and neurochemistry biomarkers of synaptic plasticity in AMY and aHIP. HRV indices were obtained from the resting state electrocardiogram of patients with drug-resistant mesial temporal lobe epilepsy (MTLE, n = 18) and the levels of P-GluA1-Ser845 and P-GluA1-Ser831 in the AMY and aHIP resected during the epilepsy surgery. A backward stepwise multiple linear regression models were used to analyze the association between HRV and synaptic plasticity biomarkers controlling for imbalances in the distribution of sociodemographic, clinical, neuroimaging, and neurosurgical variables. P-GluA1-Ser845 levels in AMY show a negative association (p < 0.05) with the 3 investigated parasympathetic autonomic HRV indices (SDNN, rMSSD, and HF) predicting 24 to 40% of their variation. The final multiple linear regression models include disease duration and levels of P-GluA1-Ser845 and predict 24 to 56% of cardiac autonomic tone variation (p < 0.01). P-GluA1-Ser845 levels in AMY and aHIP are negatively associated with the resting HRV in MTLE-HS indicating that increased synaptic efficiency in amygdala is associated with a parasympathetic cardiac autonomic tone impairment. The results suggest that specific changes in synaptic plasticity may be involved in the brain-heart axis regulation by the limbic system. [ABSTRACT FROM AUTHOR]

Fluoxetine is the foremost prescribed antidepressant. Drugs acting on monoaminergic system may also regulate glutamatergic system. Indeed, the investigation of proteins associated with this system, such as Narp (neuronal activity-dependent pentraxin) and GluA4 subunit of AMPA receptor may reveal poorly explored modulations triggered by conventional antidepressants. This study aimed to uncover neurochemical mechanisms underlying the chronic fluoxetine treatment, mainly by evaluating these protein targets in the prefrontal cortex and in the hippocampus. Mice received a daily administration of fluoxetine (0.1, 1 or 10 mg/kg, p.o.) or potable water (vehicle group) for 21 days. These animals were submitted to the forced swim test (FST) to verify antidepressant-like responses and the open-field test (OFT) to assess locomotor activity. Modulation of signaling proteins was analyzed by western blot. Chronic treatment with fluoxetine (1 and 10 mg/kg) was effective, since it reduced the immobility time in the FST, without altering locomotor activity. Fluoxetine 10 mg/kg increased CREB phosphorylation and BDNF expression in the prefrontal cortex and hippocampus. Noteworthy, in the hippocampus fluoxetine also promoted Akt activation and augmented Narp expression. In the prefrontal cortex, a significant decrease in the expression of the GluA4 subunit and Narp were observed following fluoxetine administration (10 mg/kg). The results provide evidence of novel molecular targets potentially involved in the antidepressant effects of fluoxetine, since in mature rodents Narp and GluA4 are mainly expressed in the GABAergic parvalbumin-positive (PV+) interneurons. This may bring new insights into the molecular elements involved in the mechanisms underlying the antidepressant effects of fluoxetine. [ABSTRACT FROM AUTHOR]

The quantitative analysis of electroencephalogram (qEEG) is a suitable tool for mental fatigue (MF) assessment. Here, we evaluated the effects of MF on behavioral performance and alpha power spectral density (PSD) and the association between early alpha PSD reactivity and long-term behavioral MF impairments. Nineteen right-handed adults (21.21 ± 1.77 years old) had their EEG measured during five blocks of the visual oddball paradigm (~ 60 min). A paired t-test was used to compare first and last block values of cognitive performance and alpha PSD. The sample was divided into high (HAG) and low alpha group (LAG) by early alpha PSD median values. The behavioral performance of the HAG and LAG was compared across the blocks by a two-way ANOVA with repeated measures (groups and blocks). MF impairs general behavioral performance and increases alpha PSD. The HAG presents more behavioral impairment when compared to LAG across the task. Simple linear regression between early alpha PSD and behavioral performance across the task can predict 19 to 39% of variation in general behavior impairment by MF. In conclusion, MF induction impairs general behavioral and increases alpha PSD. The other finding was that higher alpha PSD reactivity is associated to higher long-term behavioral impairments of MF. This work contributes to existing knowledge of MF by providing evidence that the possibility of investigating early electrophysiological biomarkers to predict long-term MF impairments. [ABSTRACT FROM AUTHOR]

Excessive mental workload represent a critical risk factor for workplace accidents. Heart rate variability (HRV) is a non-invasive low cost electrophysiological autonomic biomarker related to emotional and cognitive regulation. Several studies report that mental overload impairs parasympathetic-mediated HRV indices (e.g. rMSSD). However, the influence of resting state HRV as a predictor of long-term mental workload impairments remains unknown. Thirty participants (22 males; 8 females) had their HRV measured (5-min period) before performing the number search task. After the task, the mental load was accessed by the NASA-TLX questionnaire. A simple linear regression model between HRV and NASA-TLX dimensions showed that resting state rMSSD is associated to physical demand (ND-2, R2 = 0.143, p = 0.03) and frustration level (ND-6, R2 = 0.175, p = 0.02) dimensions of mental workload. The comparison between 1 and 5-min epochs suggests that regression models remain reliable even using the ultra-short term HRV (< 1 min) recording values (R2 values from 0.11 to 0.15 for ND-2 and R2 values from 0.16 to 0.19 for ND-6). These results suggest that resting state HRV is associated to long-term effects of mental workload on physical and emotional demands. In addition, the ultra-short term HRV indices remains reliable to assess ND-2 and ND-6 dimensions of mental workload when compared to gold-standard time interval (> 5 min). The resting state cardiac autonomic tone assessment optimizes the physiological approach with a quick, non-invasive and low-cost assessment that can provide insights about mental load adjustments to prevent work-related accidents. [ABSTRACT FROM AUTHOR]

Chronic metabolic alterations may represent a risk factor for the development of cognitive impairment, dementia, or neurodegenerative diseases. Hyperglycemia and obesity are known to imprint epigenetic markers that compromise the proper expression of cell survival genes. Here, we showed that chronic hyperglycemia (60 days) induced by a single intraperitoneal injection of streptozotocin compromised cognition by reducing hippocampal ERK signaling and by inducing neurotoxicity in rats. The mechanisms appear to be linked to reduced active DNA demethylation and diminished expression of the neuroprotective transcription factor REST. The impact of the relationship between adiposity and DNA hypermethylation on REST expression was also demonstrated in peripheral blood mononuclear cells in obese children with reduced levels of blood ascorbate. The reversible nature of epigenetic modifications and the cognitive impairment reported in obese children, adolescents, and adults suggest that the correction of the anthropometry and the peripheral metabolic alterations would protect brain homeostasis and reduce the risk of developing neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Persistent inflammation in intensive care unit (ICU) survivors is associated with higher long-term mortality and poorer mobility. However, it is unknown if inflammatory markers are associated with other dysfunctions observed in survivors of critical illness. Thus, it was investigated if plasma levels of interleukin (IL)-6 and IL-10 at hospital discharge were associated with long-term functional and cognitive performance after ICU discharge. Adult patients admitted for > 48 h to a 20-bed mixed ICU in a University Hospital had blood collected within 48 h before hospital discharge to measure IL-6 and IL-10 levels. After a median time of 48 months, cognitive status was determined by the Mini-Mental State Examination (MMSE), and functional status was determined by the Barthel Index. Patients at the higher 25th percentile of both IL-6 and IL-10 had a worse long-term cognitive performance, but not worse functional status, even when adjusted for confounders after long-term follow-up. In conclusion, elevated circulating IL-6 and IL-10 concentrations at hospital discharge were associated with long-term cognitive dysfunction in ICU survivors. [ABSTRACT FROM AUTHOR]

Depression is a highly prevalent and debilitating non-motor symptom observed during the early stages of Parkinson’s disease (PD). Although PD prevalence is higher in men, the depressive symptoms in PD are more common in women. Therefore, the aim of this study was to investigate the development of anhedonic- and depressive-like behaviors in male and female mice and the potential mechanisms related to depressive symptoms in an experimental model of PD. Young adult male and female C57BL/6 mice (3 months old) received a single intranasal (i.n.) administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and were submitted to a battery of behavioral tasks (sucrose consumption, splash test, tail suspension, forced swimming and open field tests) to assess their emotional and motor profiles. Considering the role of sexual hormones in emotional behaviors, the same protocol of i.n. MPTP administration and the splash, tail suspension, and open field tests were conducted in ovariectomized (OVX) and aged C57BL/6 female (20 months old) mice. We also investigated the immunocontent of neurotrophins (BDNF, GDNF, and VEGF) in the hippocampus and prefrontal cortex by western blot. I.n.  MPTP administration induced more pronounced anhedonic- and selective depressive-like behaviors in female adult mice, also observed in OVX and aged female mice, with the absence of motor impairments. Furthermore, MPTP induced a more pronounced depletion of neurotrophins in the prefrontal cortex and hippocampus in female than male mice. This study provides new evidence of increased susceptibility of female mice to anhedonic- and depressive-like behaviors following i.n. MPTP administration. The observed gender-related effects of MPTP on emotional parameters seem to be linked to increased depletion of neurotrophins (particularly BDNF and GDNF) in the hippocampus and prefrontal cortex of female mice. [ABSTRACT FROM AUTHOR]

Deep brain stimulation (DBS) benefits Parkinson's disease (PD) patient's quality of life specially in domains as mobility, activities of daily living (ADL) and bodily discomfort (BD), but little is known about the variables associated with these HRQOL domains in patients presenting for DBS. The objective is to evaluate variables associated with of HRQOL in a Brazilian sample of PD patients presenting for DBS treatment, specifically in the domains related with motor symptoms. In a cross-sectional study of 59 PD patients evaluated at outpatient Unit for Movement Disorders, multiple linear regression analysis was performed to identify independent variables associated with mobility, ADL and BD domains of the 39-item Parkinson's disease questionnaire (PDQ-39). UPDRS III "on" scores, duration of the disease, age, presence of comorbidities and anxiety and depressive symptoms quantified by hospital anxiety and depression scale (HADS), were the independent variables. In our results, HADS scores were independently associated to mobility domain: β coefficient 1.36 (95 % CI 0.55-2.15) and BD domain: β coefficient 1.57 (95 % CI 0.67-2.48). UPDRS III "on" scores were independently associated to mobility domain: 0.42 (95 % CI 0.03-0.81). The model of each multiple linear regression analysis explains 25 % of the mobility domain variability (p < 0.01) and 24 % of the BD domain variability (p < 0.01). Psychiatric symptoms were at least as relevant to quality of life as motor symptoms in PD patients presenting for DBS treatment. The effect of treating these psychiatric symptoms on patients' HRQOL deserves further investigation. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinases (MAPKs) are a group of serine-threonine kinases, including p38, ERK 1/2 and JNK p54/p46, activated by phosphorylation in response to extracellular stimuli. The early postnatal period is characterized by significant changes in brain structure as well as intracellular signaling. In the hippocampus MAPKs have been involved in the modulation of development and neural plasticity. However, the temporal profile of MAPK activation throughout the early postnatal development is incomplete. An understanding of this profile is important since slight changes in the activity of these enzymes, in response to environmental stress in specific developmental windows, might alter the course of development. The present study was undertaken to investigate the hippocampal differential activation of MAPK during postnatal period. MAPK activation and total content were evaluated by Western blotting of hippocampal tissue obtained from male Wistar rats at postnatal days (P) 1, 4, 7, 10, 14, 21, 30 and 60. The total content and phosphorylation of each MAPK was expressed as mean ± SEM and then calculates as a percentile compared to P1 (set at 100 %). The results showed: (1) phosphorylation peaks of p38 at PN4 ( p = 0.036) and PN10 to PN60; (2) phosphorylation of ERK1 and ERK2 were increased with age (ERK1 p = 0.0000005 and ERK2 p = 0.003); (3) phosphorylation profile of JNK p54/p46 was not changed during the period analyzed (JNKp56 p = 0.716 and JNKp46 p = 0.192). Therefore, the activity profile of ERK 1/2 and p38 during postnatal development of rat hippocampus are differentially regulated. Our results demonstrate that ERK 1/2 and p38 are dynamically regulated during postnatal neurodevelopment, suggesting temporal correlation of MAPK activity with critical periods when programmed cell death and synaptogenesis are occurring. This suggests an important role for these MAPKs in postnatal development of rat hippocampus. [ABSTRACT FROM AUTHOR]

Mitochondrial respiratory chain complexes enzymatic (MRCCE) activities were successfully evaluated in frozen brain samples. Epilepsy surgery offers an ethical opportunity to study human brain tissue surgically removed to treat drug resistant epilepsies. Epilepsy surgeries are done with hemodynamic and laboratory parameters to maintain physiology, but there are no studies analyzing the association among these parameters and MRCCE activities in the human brain tissue. We determined the intra-operative parameters independently associated with MRCCE activities in middle temporal neocortex (Cx), amygdala (AMY) and head of hippocampus (HIP) samples of patients (n = 23) who underwent temporal lobectomy using multiple linear regressions. MRCCE activities in Cx, AMY and HIP are differentially associated to trans-operative mean arterial blood pressure, O saturation, hemoglobin, and anesthesia duration to time of tissue sampling. The time-course between the last seizure occurrence and tissue sampling as well as the sample storage to biochemical assessments were also associated with enzyme activities. Linear regression models including these variables explain 13-17 % of MRCCE activities and show a moderate to strong effect (r = 0.37-0.82). Intraoperative hemodynamic and laboratory parameters as well as the time from last seizure to tissue sampling and storage time are associated with MRCCE activities in human samples from the Cx, AMYG and HIP. Careful control of these parameters is required to minimize confounding biases in studies using human brain samples collected from elective neurosurgery. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) patients have an increased risk of falls resulting in important social and economical consequences. Risk factors for falls include the use of psychotropic drugs, which are used for the treatment of PD neuropsychiatric symptoms. We aimed to determine the association between psychotropic drug use and falls in a PD cohort. A cross-sectional study from the NPF QII study UF site was conducted. Subjects reported presence and frequency of falls in the prior year. Frequency was scored from 0 (no falls) to 4 (falling daily). Antidepressants, antipsychotics, cognitive enhancers/stimulants, and benzodiazepines were considered psychotropics. Forty percent of the 647 subjects included had a fall in the previous year. Fallers were found to have clinical signs of a more advanced disease. After adjusting for confounding variables, the regression analysis showed that use of antidepressants alone (adjusted OR 2.2, CI 95 % 1.3-3.8, p = 0.04), benzodiazepines alone (adjusted OR 2.0, CI 95 % 1.1-3.5, p = 0.02), and the combination of antidepressants with benzodiazepines (adjusted OR 4.1, CI 95 % 2.0-8.3, p < 0.0001) were independently associated with the presence of falls. When comparing to those not on psychotropics, subjects on antidepressants alone had a significantly higher mean frequency of falls score (1.07 vs. 0.44, p < 0.0001). The use of antidepressants was independently associated with falls in our PD cohort after considering for confounding variables such as age and measures of disease progression. Other factors related to disease progression should be considered before claiming the use of psychotropic drugs as causative. [ABSTRACT FROM AUTHOR]

The epileptogenesis process involves cell signaling events associated with neuroplasticity. The mitogen-activated protein kinases (MAPKs) integrate signals originating from a variety of extracellular stimuli and may regulate cell differentiation, survival, cell death and synaptic plasticity. Here we compared the total and phosphorylated MAPKs (ERK1/2, JNK1/2 and p38) levels in the neocortex and hippocampus of adult Swiss male mice quantified by western blotting analysis 48 h after the last injection of pentylenetetrazole (PTZ), according to the kindling protocol (35 mg/kg, i.p., on alternated days, with a total of eight injections). The total levels of the investigated MAPKs and the phospho-p38 in the neocortex and hippocampus were not affected by the PTZ injections. The MAPKs phosphorylation levels remain unaltered in PTZ-treated animals without convulsive seizures. The phospho-JNK2 phosphorylation, but not the phospho-JNK1, was increased in the hippocampus of PTZ-treated animals showing 1-3 days with convulsive seizures, whereas no significant changes were observed in those animals with more than 3 days with convulsive seizures. The phospho-ERK1/2 phosphorylation decreased in the neocortex and increased in the hippocampus of animals with 1-4 days with convulsive seizures and became unaltered in mice that showed convulsive seizures for more than 4 days. These findings indicate that resistance to PTZ kindling is associated with unaltered ERK1/2, JNK1/2 and p38 phosphorylation levels in the neocortex and hippocampus. Moreover, when the PTZ kindling-induced epileptogenesis manifests behaviorally, the activation of the different MAPKs sub-families shows a variable and non-linear pattern in the neocortex and hippocampus. [ABSTRACT FROM AUTHOR]

We compared the lifetime prevalence and the prevalence of headache during the previous year in patients with Parkinson's disease (PD) and control subjects. We also investigated the association between the side of PD symptom onset and the side of the headache. We interviewed 98 consecutive patients with an established diagnosis of PD between December 2010 and January 2012. The control group consisted of the 98 oldest sex-matched individuals from the nationwide Brazilian headache database. PD patients showed a significantly lower prevalence (40.8 %) of headache in the previous year than controls (69.4 %) (adjusted OR 0.5, CI 95 % 0.2-0.9, p = 0.03). PD patients also showed a lower prevalence of headache throughout life (74.5 %) than controls (93.9 %) (adjusted OR 0.2, CI 95 % 0.1-0.6, p = 0.01). Considering only patients who presented headache during the previous year, PD patients showed a higher association with occurrence of migraine than tension-type headache compared with controls (adjusted OR 3.3, CI 95 % 1.2-8.9, p = 0.02). The headache side was ipsilateral to the side of PD onset in 21 patients (84 %), with a concordance of 85.7 % on the left side and 81.8 % on the right side ( p < 0.01). The prevalence of primary headache was significantly lower in patients with PD than controls. The predominant side of headache was ipsilateral to the side of initial motor signs of PD. [ABSTRACT FROM AUTHOR]

Epidemiological studies have indicated hypercholesterolemia in midlife as a risk factor for dementia in later life, bringing cholesterol to the forefront of Alzheimer's disease research. Herein, we modeled mild hypercholesterolemia in mice to evaluate biochemical and behavioral alterations linked to hypercholesterolemia. Swiss mice were fed a high fat/cholesterol diet (20 % fat and 1.25 % cholesterol) for an 8-week period (from 12 to 18 weeks old) and were tested on the object location, forced swimming and elevated plus-maze tasks. We also investigated hypercholesterolemia-induced changes on acetylcholinesterase (AChE) activity, oxidative damage, amyloid precursor protein (APP) processing and blood brain barrier (BBB) integrity within the prefrontal cortex and hippocampus. It was found that increased AChE activity within the prefrontal cortex and hippocampus is an early event associated with hypercholesterolemia-induced short-term memory impairments. We observed no signs of antioxidant imbalance and/or oxidative damage or changes in cortical and hippocampal densities of beta-site amyloid precursor protein-cleaving enzyme 1 and aquaporin-4, biomarkers of APP processing and BBB integrity, respectively. In addition, we treated SH-SY5Y human neuroblastoma cells with low-density lipoprotein (LDL) cholesterol in an attempt to manipulate cell cholesterol content. Notably, LDL cholesterol increased in a dose-dependent manner the activity of AChE in SH-SY5Y cells. The present findings provide new evidence that increased AChE activity within the prefrontal cortex and hippocampus is an early event associated with hypercholesterolemia-induced cognitive impairments. [ABSTRACT FROM AUTHOR]

The cellular prion protein, encoded by Prnp gene, is involved in neuroprotection, neuroplasticity and neurodevelopment. The variant allele Valine at codon 129 of the Prnp was associated with decreased brain volume in healthy volunteers and schizophrenic patients. We investigate the association between the cerebellum volume and the presence of variant allele Valine at codon 129 of the Prnp gene in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). The Prnp coding sequence was determined in 41 refractory MTLE-HS patients. The cerebellum volume corrected by the intracranial volume of patients with the normal Prnp genotypes was compared with that of patients presenting the variant alleles at codon 129. Twenty patients showed the Met129Met genotype, 16 showed Met129Val, and 5 had Val129Val. There were no association among clinical, demographic, electrophysiological, antiepileptic drugs used, and the presence of the Prnp variant alleles. The presence of Prnp variant allele at codon 129 was not associated with the analyzed cerebellum volume. Prnp variant alleles at codon 129 are not associated with cerebellum volume in patients with refractory MTLE-HS. [ABSTRACT FROM AUTHOR]

The pilocarpine model in rodents reproduces the main features of mesial temporal lobe epilepsy related to hippocampus sclerosis (MTLE-HS) in humans. It has been demonstrated in this model that the phosphorylation of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR1 subunit is increased 1 h after pilocarpine treatment. Moreover, alterations in the levels of glutamate transporters have been associated with chronic epilepsy in humans. Despite these studies, the profile of these changes has not yet been addressed. We analyzed the protein content and phosphorylation profile of the AMPA receptor GluR1 subunit by western blotting. We also used quantitative real-time polymerase chain reaction to analyze the expression of glial glutamate transporters and the N-methyl- d-aspartate receptor NR1 subunit in the hippocampus (Hip) and cerebral cortex (Ctx) at different time points after pilocarpine-induced status epilepticus (Pilo-SE) in male adult Wistar rats. Biochemical analysis was performed in the Hip and Ctx at 1, 3, 12 h (acute period), 5 days (latent period), and 50 days (chronic period) after Pilo-SE. Key findings include an increase in the phosphorylation of GluR1-Ser in the Ctx and GluR1-Ser in the Hip at different times during the acute period, and a decrease in the total content of the GluR1 subunit in the Ctx in the latent period. There was a down-regulation of the mRNA expression and protein levels of EAAT1 and EAAT2, and a decrease of the NR1 mRNA expression, in the Ctx during the latent period. Notably, during the chronic period, the EAAT2 mRNA expression and protein levels decreased while the NR1 mRNA levels increased in the Hip. Taken together, our findings suggest a time- and structure-dependent imbalance of glutamatergic transmission in response to Pilo-SE, which might be associated with either epileptogenesis or the seizure threshold in MTLE-HS. [ABSTRACT FROM AUTHOR]

The epileptogenesis may involve a variety of signaling events that culminate with synaptic reorganization. Mitogen-activated protein kinases (MAPKs) and AKT may be activated by diverse stimulus including neurotransmitter, oxidative stress, growth factors and cytokines and are involved in synaptic plasticity in the hippocampus and cerebral cortex. The pilocarpine model in rodents reproduces the main features of mesial temporal lobe epilepsy related to hippocampus sclerosis (MTLE-HS) in humans. We analyze the phosphorylation profile of MAPKs (ERK1/2, p38, JNK1/2/3) and AKT by western blotting in the hippocampus (Hip) and cortex (Ctx) of male adult wistar rats in different periods, after pilocarpine induced status epilepticus (Pilo-SE) and compared with control animals. Biochemical analysis were done in the Hip and Ctx at 1, 3, 12 h (acute period), 5 days (latent period) and 50 days (chronic period) after Pilo-SE onset. Hence, the main findings include increased phosphorylation of ERK1 and p38 in the Hip and Ctx 1 and 12 h after the Pilo-SE onset. The JNK2/3 isoform (54 kDa) phosphorylation was decreased at 3 h after the Pilo-SE onset and in the chronic period in the Hip and Ctx. The AKT phosphorylation increased only in the Hip during the latent period. Our study demonstrates, in a systematic manner, the profile of MAPKs and AKT modulation in the hippocampus and cerebral cortex in response to pilocarpine. Based in the role of each signaling enzyme is possible that these changes may be related, at least partially, to modifications in the intrinsic neuronal physiology and epileptogenic synaptic network that appears in the MTLE-HS. [ABSTRACT FROM AUTHOR]

The causes of Parkinson's disease (PD) are unknown, but there is evidence that exposure to environmental agents, including a number of viruses, toxins, agricultural chemicals, dietary nutrients, and metals, is associated with its development in some cases. The presence of smell loss and the pathological involvement of the olfactory pathways in the early stages of PD are in accord with the tenants of the olfactory vector hypothesis. This hypothesis postulates that some forms of PD may be caused or catalyzed by environmental agents that enter the brain via the olfactory mucosa. In this article, we provide an overview of evidence implicating xenobiotics agents in the etiology of PD and review animal, mostly rodent, studies in which toxicants have been introduced into the nose in an attempt to induce behavioral or neurochemical changes similar to those seen in PD. The available data suggest that this route of exposure results in highly variable outcomes, depending upon the involved xenobiotic, exposure history, and the age and species of the animals tested. Some compounds, such as rotenone, paraquat, and 6-hydroxydopamine, have limited capacity to reach and damage the nigrostriatal dopaminergic system via the intranasal route. Others, such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), readily enter the brain via this route in some species and influence the function of the nigrostriatal pathway. Intranasal infusion of MPTP in some rodents elicits a developmental sequence of behavioral and neurochemical changes that closely mimics that seen in PD. For this reason, such an MPTP rodent model appears to be an ecologically valid means for assessing novel palliative treatments for both the motor and non-motor symptoms of PD. More research is needed, however, on this and other ecologically valid models. [ABSTRACT FROM AUTHOR]

Background: Traumatic brain injury (TBI) is a worldwide cause of morbidity and mortality. Pentraxin 3 (PTX3) is a humoral component of the innate immune system which has been studied as a marker of inflammatory, infections or cardiovascular pathologies. To investigate the association between serum levels of PTX3 and the hospital mortality of patients with severe TBI. Methods: The independent association between serum PTX3 levels after severe TBI (Glasgow Coma Scale, GCS ≤ 8) and hospital mortality was analyzed in a prospective study of 83 consecutive patients by a multiple logistic regression analysis. The leukocyte count in the same sample was analyzed as another marker of inflammatory response. Results: The mean age of patients was 35 years and 85% were male. Serum PTX3 levels were determined 18.0 (SD ± 17.0) h after TBI. Patients who died showed a mean serum PTX3 level of 9.95 μg/ml (SD ± 6.42) in comparison to 5.46 μg/ml (SD ± 4.87) of the survivor group ( P = 0.007). Elevated serum PTX3 levels remain significantly associated with mortality ( P = 0.04) in the subset of patients with isolated TBI ( n = 34). There were no differences in the leukocytes count measured in the same blood sample used for PTX3 determination in survivors and non-survivors ( P = 0.56). The final multiple logistic regression model including age, pupillary examination, GCS, associated trauma, and PTX3 levels shows that serum levels of PTX3 which were higher than 10 μg/ml were independently associated with the patients mortality (adjusted OR 3.06, CI 95% 1.03-9.15, P = 0.04). Conclusions: Serum PTX3 levels after severe TBI are independently associated with higher hospital mortality and may be a useful marker of TBI and its prognosis. [ABSTRACT FROM AUTHOR]

1. Cellular prion (PrPc) is a plasma membrane protein involved with copper uptake, protection against oxidative stress, cell adhesion, differentiation, signaling, and survival in the central nervous system 2. Deletion of PrPc gene ( Prnp) in mice enhances sensitivity to seizures in vivo and neuronal excitability in vitro which can be related to: (i) disrupted Ca+2-activated K+ currents, with loss of IHAP conductance in hippocampus; (ii) abnormal GABA-A inhibition in the hippocampus; (iii) mossy fiber reorganization in the hippocampus; (iv) changes in ectonucleotidases in both hippocampus and neocortex; and (v) higher levels of neocortical and subcortical oxidative stress. Moreover, postnatal Prnp knockout mice showed a significant reduction of after hyperpolarization potentials in hippocampal CA1 cells. 3. Taken together, these findings suggest that loss of PrPc function contributes to the hyperexcitable and synchronized activities underlying epileptic seizures generated in neocortex and hippocampus. Hence, the role of PrPc on human symptomatic, cryptogenic or idiopathic epileptic syndromes deserves further investigation. [ABSTRACT FROM AUTHOR]

The ectonucleotidase pathway is an important metabolic source of extracellular adenosine. Adenosine has potent anticonvulsant effects on various models of epilepsy. One of these models is pentylenetetrazol (PTZ) kindling, in which repeated administration of subconvulsive doses of this drug induces progressive intensification of seizure activity. In this study, we examine the effect of a single convulsive injection (60 mg/kg, i.p.) or 10 successive (35 mg/kg, i.p.) injections of PTZ on synaptosomal ectonucleotidases. Our results have shown that no changes in ectonucleotidase activities were seen at 0, 1, and 24 h or at 5 days after a single convulsive PTZ injection. However, after PTZ-kindling, rats which were more resistant to seizure development presented an increase in ATP hydrolysis in synaptosomes from hippocampus and cerebral cortex (44% and 28%, respectively). These results suggest that changes in nucleotide hydrolysis may represent an important mechanism in the modulation of chronic epileptic activity in this model. [ABSTRACT FROM AUTHOR]