Evaluation of antibody titers in COVID-19 patients with cerebral or pulmonary symptoms and mild symptoms.

Background and Objectives: This study aimed to compare the production of antibodies in three different groups of patients with COVID-19. These groups included patients with pulmonary and cerebral symptoms, as well as those with mild symptoms. Materials and Methods: Blood samples were collected from 80 patients admitted to COVID-19-specific hospitals. The patients had various forms of SARS-CoV-2 disease, including those with pulmonary symptoms, brain involvement, and those with positive PCR test results but mild symptoms. The enzyme-linked immunosorbent assay (ELISA) technique was used to determine the levels of IgM and IgG antibody titers. Results: The levels of IgM and IgG antibody production differed significantly between groups of patients experiencing pulmonary symptoms and cerebral symptoms, with mild symptom patients also showing differences (P=0.0068), (P=0.0487), (P<0.0001), and (P=0.0120), respectively. Furthermore, there was no significant relationship between IgM antibody secretion and age or pulmonary involvement (P=0.1959). However, there was a direct and significant relationship between age and brain involvement (P=0.0317). Conclusion: The findings of this study revealed that the risk of central nervous system involvement increases with age and that older people have lower antibody levels than younger people. Consequently, strengthening the immune systems of people over the age of 78 during this pandemic through vaccination and nutrition is very effective in reducing mortality in this age group.

Evaluation of the relationship between serum BDNF concentration and indicators of oxidative stress and inflammation in COVID-19 patients with neurological disorders - a pilot study.

INTRODUCTION: The aim of this study was to determine the effect of serum level of brain-derived neurotrophic factor (BDNF) on the development of neurological disorders in COVID-19 patients and the probable role of oxidative stress and inflammation in this phenomenon. METHODS: The present case-control study included 42 COVID-19 patients referring to Golestan and Sina hospitals of Ahvaz, Iran, for treatment. Patients with (n = 18) and without (n = 24) neurological disorders were allocated into test and control groups, respectively. Following blood sampling, serum isolation was done, and the serum was stored at -80°C until biochemical assessment for measuring BDNF, oxidative stress indices, and inflammatory factors. RESULTS: Although no significant brain damage was observed in the COVID-19 patients with neurological disorders, the results showed that the serum level of BDNF in the test group increased compared to that in the control group, and this increment was accompanied with increased Tumor Necrosis Factor-alpha (TNF-α) and decreased Interferon gamma (IFN-γ) levels in the serum. Moreover, compared to the control group, patients in the test group had a decreased level of Thiol and an increased level of Malondialdehyde (MDA) in the serum. Furthermore, there was a significant positive correlation between the serum concentration of BDNF and nitric oxide (NO) in the test group. CONCLUSION: Using over-the-counter (OTC) medicines which include thiol-group-related agents or any other antioxidants can alleviate oxidative stress and the associated increased inflammation in COVID-19 patients with neurological symptoms.

Anethole attenuates motor dysfunctions, striatal neuronal activity deficiency and blood brain barrier permeability by decreasing striatal α-synuclein and oxidative stress in rotenone-induced Parkinson's disease of male rats.

INTRODUCTION: Anethole is the main compound of the essential oil of anise and several other plants, which has antioxidant, anti-inflammatory, and neuroprotective properties. Oxidative stress is considered as an important factor in the pathogenesis of PD. In the present study, we aimed to investigate the effects of anethole against rotenone-induced PD. METHODS: Male Wistar rats were randomly divided into six groups. Control group received DMSO + sunflower oil, model group received rotenone (2 mg/kg, s.c, daily for 35 days), positive control group received L-Dopa, and test groups received anethole (62.5, 125, and 250 mg/kg, i.g, daily for 35 days) 1 hour before each rotenone injection. Body weight changes, rotarod test, stride length test, and extracellular single unit recording were performed after treatment. After behavioral test, Brain water content and blood brain barrier (BBB) permeability were evaluated, and the levels of malondialdehyde (MDA), superoxide dismutases (SOD), alpha-synuclein and MAO-B were measured in the striatum. RESULTS: Chronic administration of rotenone induced body weight loss and caused significant dysfunction in locomotor activity, neuronl firing rate, and BBB. Rotenone also decreased SOD activity, increased MDA level, and elevated the expression of alpha-synuclein and MAO-B in the striatum. However, treatment with anethole attenuated body weight loss, motor function, neuronal activity, and BBB function. Furthermore, Anethole treatment attenuated oxidative stress and decreased the expression of alpha-synuclein and MAO-B compared to the rotenone group. CONCLUSION: Our results show that through its antioxidant properties, aethole can improve the cellular, molecular and behavioral characteristics of rotenone-induced Parkinson's disease.

Anti-inflammatory, anti-apoptotic, and neuroprotective potentials of anethole in Parkinson's disease-like motor and non-motor symptoms induced by rotenone in rats.

Parkinson's disease (PD) is a complex neurological disorder characterized by a combination of motor and non-motor symptoms (NMS). Antioxidant and anti-inflammatory compounds are considered a potential therapeutic strategy against PD. The present study examined the neuroprotective effects of anethole as a potent antioxidant and anti-inflammatory agent against motor and non-motor deficits induced by rotenone toxicity. Rats were treated with anethole (62.5, 125, and 250 mg/kg, i.g) concomitantly with rotenone (2 mg/kg, s.c) for 5 weeks. After the treatment, behavioral tests were performed to evaluate motor function and depression-/anxiety-like behaviors. After the behavioral tests, rats were decapitated and brains were removed for histological analysis. Striatum samples were also isolated for neurochemical, and molecular analysis. Our data showed that rotenone-induced motor deficit, anxiety-and depression-like behaviors were significantly improved in rats treated with anethole. Furthermore, anethole treatment reduced inflammatory cytokines tumor necrosis factor α (TNFα) and Interleukin 6 (IL-6), and increased anti-inflammatory cytokine IL-4 in the striatum of rotenone-induced PD rats. Western blot analysis showed that treatment with anethole markedly suppressed caspase-3 activation induced by rotenone. Moreover, histological examination of striatum showed an increase in the number of surviving neurons after treatment with anethole. Anethole also significantly enhanced the striatal levels of dopamine in rotenone-induced PD rats. In addition, treatment with L-Dopa as a positive control group had effects similar to those of anethole on histological, neurochemical, and molecular parameters in rotenone-induced parkinsonian rats. Our results suggested the neuroprotective effects of anethole through anti-inflammatory, anti-apoptotic, and antioxidant mechanisms against rotenone-induced toxicity in rats.

Exogenous growth hormone administration during total sleep deprivation changed the microRNA-9 and dopamine D2 receptor expressions followed by improvement in the hippocampal synaptic potential, spatial cognition, and inflammation in rats.

RATIONALE: Disorders caused by total sleep deprivation can be modulated by the administration of growth hormone, which could affect the expression of microRNA-9 and dopamine D2 receptor expressions followed by improvement in the hippocampal synaptic potential, spatial cognition, and inflammation in rats. OBJECTIVES: The present study aimed to elucidate the putative effects of exogenous growth hormone (GH) against total sleep deprivation (TSD)-induced learning and memory dysfunctions and possible involved mechanisms. METHODS: To induce TSD, rats were housed in homemade special cages equipped with stainless steel wire conductors to induce general and inconsistent TSD. They received a mild repetitive electric shock to their paws every 10 min for 21 days. GH (1 mg/kg, sc) was administered to adult young male rats once daily for 21-day-duration induction of TSD. Spatial learning and memory performance, inflammatory status, microRNA-9 (miR-9) expression, dopamine D2 receptor (DRD2) protein level, and hippocampal histological changes were assayed at scheduled times after TSD. RESULTS: The results indicated that TSD impaired spatial cognition, increased TNF-α, decreased level of miR-9, and increased DRD2 levels. Treatment with exogenous GH improved spatial cognition, decreased TNF-α, increased level of miR-9, and decreased DRD2 levels after TSD. CONCLUSIONS: Our findings suggest that GH may play a key role in the modulation of learning and memory disorders as well as the ameliorating abnormal DRD2-related functional disorders associated with miR-9 in TSD.

Administration of growth hormone ameliorates adverse effects of total sleep deprivation.

Total sleep deprivation (TSD) causes several harmful changes including anxiety, inflammation, and increased expression of extracellular signal-regulated kinase (ERK) and tropomyosin receptor kinase B (TrkB) genes in the hippocampus. The current study was conducted to explain the possible effects of exogenous GH against the above parameters caused by TSD and the possible mechanisms involved. Male Wistar rats were divided into 1) control, 2) TSD and 3) TSD + GH groups. To induce TSD, the rats received a mild repetitive electric shock (2 mA, 3 s) to their paws every 10 min for 21 days. Rats in the third group received GH (1 ml/kg, sc) for 21 days as treatment for TSD. The motor coordination, locomotion, the level of IL-6, and expression of ERK and TrkB genes in hippocampal tissue were measured after TSD. The motor coordination (p < 0.001) and locomotion indices (p < 0.001) were impaired significantly by TSD. The concentrations of serum corticotropin-releasing hormone (CRH) (p < 0.001) and hippocampal interleukin-6 (IL-6) (p < 0.001) increased. However, there was a significant decrease in the interleukin-4 (IL-4) concentration and expression of ERK (p < 0.001) and TrkB (p < 0.001) genes in the hippocampus of rats with TSD. Treatment of TSD rats with GH improved motor balance (p < 0.001) and locomotion (p < 0.001), decreased serum CRH (p < 0.001), IL-6 (p < 0.01) but increased the IL-4 and expression of ERK (p < 0.001) and TrkB (p < 0.001) genes in the hippocampus. Results show that GH plays a key role in modulating the stress hormone, inflammation, and the expression of ERK and TrkB genes in the hippocampus following stress during TSD.

Fingolimod Administration Following Hypoxia Induced Neonatal Seizure Can Restore Impaired Long-term Potentiation and Memory Performance in Adult Rats.

Neonatal seizures commonly caused by hypoxia can lead to long-term neurological outcomes. Early inflammation plays an important role in the pathology of these outcomes. Therefore, in the current study, we explored the long-term effects of Fingolimod (FTY720), an analog of sphingosine and potent sphingosine 1-phosphate (S1P) receptors modulator, as an anti-inflammatory and neuroprotective agent in attenuating anxiety, memory impairment, and possible alterations in gene expression of hippocampal inhibitory and excitatory receptors following hypoxia-induced neonatal seizure (HINS). Seizure was induced in 24 male and female pups (6 in each experimental group) at postnatal day 10 (P10) by premixed gas (5% oxygen/ 95% nitrogen) in a hypoxic chamber for 15 minutes. Sixty minutes after the onset of hypoxia, FTY720 (0.3 mg/kg) or saline (100 µl) was administered for 12 days (from P10 up to P21). Anxiety-like behavior and hippocampal memory function were assessed at P90 by elevated plus maze (EPM) and novel object recognition (NOR), respectively. Long-term potentiation (LTP) was recorded from hippocampal dentate gyrus region (DG) following stimulation of perforant pathway (PP). In addition, the hippocampal concentration of superoxide dismutase activity (SOD), malondialdehyde (MDA), and thiol as indices of oxidative stress were evaluated. Finally, the gene expression of NR2A subunit of N-Methyl-D-aspartic acid (NMDA) receptor, GluR2 subunit of (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) AMPA receptor and γ2 subunit of γ-Aminobutyric acid (GABAA) receptor were assessed at P90 by the quantitative real-time PCR. FTY720 significantly reduced later-life anxiety-like behavior, ameliorated object recognition memory and increased the amplitude and slope of the field excitatory postsynaptic potential (fEPSP) in the rats following HINS. These effects were associated with restoration of the hippocampal thiol content to the normal values and the regulatory role of FTY720 in the expression of hippocampal GABA and glutamate receptors subunits. In conclusion, FTY720 could restore the dysregulated gene expression of excitatory and inhibitory receptors. It also increased the reduced hippocampal thiol content, which was accompanied with attenuation of HINS-induced anxiety, reduced the impaired hippocampal related memory, and prevented hippocampal LTP deficits in later life following HINS.

Involvement of dopamine D2 -like receptors in the antiepileptogenic effects of deep brain stimulation during kindling in rats.

AIMS: Deep brain electrical stimulation (DBS), as a potential therapy for drug resistive epileptic patients, has inhibitory action on epileptogenesis. In the present investigation, the role of dopamine D2 -like receptors in the antiepileptogenic action of DBS was studied. METHODS: Seizures were induced in adult rats by stimulating the perforant path in a semi-rapid kindling method. Five minutes after the last kindling stimulation, daily DBS was applied to the perforant path at the pattern of low frequency stimulation (LFS; 1 Hz; pulse duration: 0.1 ms; intensity: 50-150 µA; 4 trains of 200 pulses at 5 min intervals). Sulpiride (10 µg/1 µl, i.c.v.), a selective dopamine D2 -like receptor antagonist, was administered prior to the daily LFS application. RESULTS: Kindling stimulations increased cumulative daily behavioral seizure stages, daily afterdischarge duration (dADD), and population spike amplitude (PS) in dentate gyrus following perforant path stimulation, while applying LFS decreased the kindled seizures' parameters. In addition, kindling potentiated the early (at 10-50 ms inter-pulse interval) and late (at 150-1000 ms inter-pulse interval) paired-pulse inhibition and decreased the paired-pulse facilitation (at 70-100 ms inter-pulse interval). These effects were also inhibited by applying LFS. All inhibitory effects of LFS on kindling procedure were prevented by sulpiride administration. CONCLUSION: These data may suggest that LFS exerts its preventive effect on kindling development, at least partly, through the receptors on which sulpiride acts which are mainly dopamine D2 -like (including D2 , D3 , and D4 ) receptors.

Neuroprotective effect of anethole against rotenone induced non-motor deficits and oxidative stress in rat model of Parkinson's disease.

INTRODUCTION: Non-motor symptoms (NMS) have high prevalence in patients with Parkinson's disease (PD). These symptoms are mainly the result of increased oxidative stress and neuronal damage. In this study we investigated the possible neuroprotective effects of anethole as a potent antioxidant on rotenone-induced behavioral deficits, hippocampal neuronal death, and oxidative stress profile in rats. METHODS: Male Wistar rats were administered with anethole (62.5, 125, and 250 mg/kg, i.g) concomitantly with rotenone (2 mg/kg, s.c) for 35 days. Shuttle box and novel object recognition tests were performed to determine cognitive functions, and tail flick test was used to measure pain sensitivity. The levels of BDNF, MDA, SOD, and GPx were assayed in the hippocampus. Hippocampal neuronal damage was evaluated using cresyl violet staining technique. RESULTS: Chronic administration of rotenone induced cognitive deficit and reduced thermal pain threshold. Rotenone also decreased SOD and GPx activities, increased MDA level, and reduced the expression of BDNF in the hippocampus. In addition, hippocampal neuronal loss was increased in rotenone treated rats. Treatment with high dose of anethole (250 mg/kg) improved cognitive function and increased pain threshold in all three doses (62.5, 125, and 250 mg/kg). Despite the unchanged SOD and GPx activities, hippocampal levels of MDA was significantly decreased after high-dose anethole treatment. Moreover, High dose of anethole increased the number of surviving neurons in the hippocampus, but couldn't increase the BDNF expression. CONCLUSION: Our findings indicated that anethole has antioxidant and neuroprotective effects against non-motor disorders induced by rotenone toxicity.

Therapeutic effects of growth hormone in a rat model of total sleep deprivation: Evaluating behavioral, hormonal, biochemical and electrophysiological parameters.

OBJECTIVE: Total sleep deprivation (TSD) causes several harmful changes in the brain, including memory impairment, increased stress and depression levels, as well as reduced antioxidant activity. Growth hormone (GH) has been shown to boost antioxidant levels while improving memory and depression. The present study was conducted to explain the possible effects of exogenous GH against behavioral and biochemical disorders caused by TSD and the possible mechanisms involved. MAIN METHODS: To induce TSD, rats were housed in homemade special cages equipped with stainless steel wire conductors to induce general and inconsistent TSD. They received a mild repetitive electric shock to their paws every 10 min for 21 days. GH (1 ml/kg, sc) was administered to rats during induction of TSD for 21 days. Memory retrieval, anxiety, depression-like behaviors, pain behaviors, antioxidant activity, hippocampal level of BDNF, and simultaneously brain electrical activity were measured at scheduled times after TSD. KEY FINDINGS: The results showed that GH treatment improved memory (p < 0.001) in the PAT test of rats exposed to TSD. These beneficial effects were associated with lowering the level of anxiety and depression-like behavior (p < 0.001), rising the pain threshold (p < 0.01), increasing the activity of antioxidants (p < 0.01), hippocampal BDNF (p < 0.001), and regular brain electrical activity. SIGNIFICANCE: Our findings show that GH plays a key role in modulating memory, anxiety and depression behaviors, as well as reducing oxidative stress and improve hippocampal single-unit activity in the brain during TSD.

Time perception impairment in multiple sclerosis patients: a survey on internal clock model.

Time perception is known as a mental ability to discern time. Although relative nature of time leaves its numerous aspects undefined, several models have been developed to describe temporal information processing in the brain as well as several areas of the brain have shown to be involved. Time perception alteration has been reported in several neurological conditions; however, the effect of multiple sclerosis (MS) on time perception has yet to be explained. In this study, we aimed to investigate the domains of temporal processing involved in patients with MS and the probable factors affecting it, such as the location of brain demyelinating plaques and gender. Two groups of participants (MS: n = 27 (8 men, 19 women), mean age = 33.85; control: n = 30 (10 men, 20 women), mean age = 28.46) were asked to perform quadruplet time perception tasks (prospective time estimation, duration discrimination, temporal reproduction, and paced motor timing) designed with a software program. Patients with MS had significantly higher scores in time estimation (p < 0.01) and duration discrimination (p < 0.001, in 100-ms interval; p < 0.05, in 1000-ms interval), indicating that MS patients overestimate the time. Since a slower internal clock for MS patients was expected as a result of axonal demyelination, these results suggest the time overestimation in patients with MS which is in contrast with the internal clock model. It means that a slow internal clock causes underestimating and perceiving the time slower.

FTY720 administration following hypoxia-induced neonatal seizure reverse cognitive impairments and severity of seizures in male and female adult rats: The role of inflammation.

Hypoxia-induced neonatal seizure mainly leads to deleterious effects on brain function, especially cognitive impairments and increased susceptibility to epilepsy later in life. Early inflammation plays an important role in the pathology of these consequences. Therefore, we explored the long-term outcomes of Fingolimod treatment as an anti-inflammatory and neuroprotective agent in a rat model of HINS. Seizures were induced in rats (postnatal day 10) by 5% O2 exposure for 15 min. Sixty minutes after the onset of hypoxia, pups received FTY720 (0.3 mg.kg-1) or normal saline for 12 consecutive days (lactation period), and they were used at P60-P63 for behavioral tests, ELISA and Pentylenetetrazole kindling model. The results of open field, novel object recognition and elevated plus maze tasks showed that Fingolimod prevents hippocampal memory dysfunction and anxiety-like behavior in both male and female hypoxic groups, which was accompanied with decreased TNF-α level in hippocampus. In addition, FTY720 postponed epileptogenesis just in female hypoxic + FTY group and decreased severity of seizures in both genders. Our results suggest that, FTY720 treatment in immature rats, which were previously subjected to HINS, prevented the long-lasting deficits, like cognitive impairments, decreased the severity of seizures and related inflammation. In addition, FTY720 did not show significant interaction with gender in most of the experiments, except the average day to reach fully kindled state. Taken together, FTY720 has therapeutic potential for long lasting effects of HINS in both male and female animals at puberty.

Objective Structured Practical Examination in Experimental Physiology Increased Satisfaction of Medical Students.

BACKGROUND: Medical education is a dynamic process, which needs to be improved to meet the new expectations of medical practitioners, health workers, and communities from different countries. An important part of medical students' education is to select an appropriate assessment method. In this regard, the objective structured practical examination (OSPE) can evaluate practical capabilities in a suitable step-wise, scientific, targeted and scheduled manner with direct consideration of student's performance during programmed test stations. The purpose of this study is to investigate the outcomes of the OSPE utilization versus traditional practical examination (TPE) for evaluating students in experimental physiology. METHODS: Totally, 120 medical students were chosen as the participants of this study: 1. TPE group (TPE used as a final exam; n=40); 2. TPE + OSPE group (TPE applied for half of topics and OSPE for another half; n=41); and 3. OSPE group (OSPE performed as a final exam; n=39). In order to evaluate the effect of OSPE, the average final grade of studied groups was compared. In addition, a 5-point Likert scale questionnaire, consisting of 10 questions was used to evaluate the students' attitudes toward using this method. RESULTS: The obtained results showed that the total grade in TPE group was significantly higher in comparison to TPE+OSPE and OSPE groups (respectively, P<0.01 and P<0.05), while according to students' expression, the average score for all of the items in feedback questionnaire was increased significantly in TPE+OSPE and OSPE groups compared with TPE group (P<0.001). CONCLUSION: In summary, feedback from students showed that they were in favor of OSPE compared with the TPE, and according to their statements in a feedback questionnaire, OSPE can improve learning in physiology as well as increasing students' satisfaction.

Deep brain stimulation restores the glutamatergic and GABAergic synaptic transmission and plasticity to normal levels in kindled rats.

BACKGROUND: The precise effect of low frequency stimulation (LFS) as a newly postulated, anticonvulsant therapeutic approach on seizure-induced changes in synaptic transmission has not been completely determined. HYPOTHESIS: In this study, the LFS effect on impaired, synaptic plasticity in kindled rats was investigated. METHODS: Hippocampal kindled rats received LFS (4 trials consisting of one train of 200 monophasic square waves, 0.1 ms pulse duration, 1 Hz) on four occasions. LTP induction was evaluated using whole-cell recordings of evoked excitatory and inhibitory post-synaptic potentials (EPSPs and IPSPs respectively) in CA1 neurons in hippocampal slices. In addition, the hippocampal excitatory and inhibitory post-synaptic currents (EPSCs and IPSCs), and the gene expression of NR2A, GluR2 and γ2 were evaluated. RESULTS: LTP induction was attenuated in excitatory and inhibitory synapses in hippocampal slices of kindled rats. When LFS was applied in kindled animals, LTP was induced in EPSPs and IPSPs. Moreover, LFS increased and decreased the threshold intensities of EPSCs and IPSCs respectively. In kindled animals, NR2A gene expression increased, while γ2 gene expression decreased. GluR2 gene expression did not significantly change. Applying LFS in kindled animals mitigated these changes: No significant differences were observed in NR2A, γ2 and GluR2 gene expression in the kindled+LFS and control groups. CONCLUSION: The application of LFS in kindled animals restored LTP induction in both EPSPs and IPSPs, and returned the threshold intensity for induction of EPSCs, IPSCs and gene expression to similar levels as controls.

Effects of Low Frequency Stimulation on Spontaneous Inhibitory and Excitatory Post-Synaptic Currents in Hippocampal CA1 Pyramidal Cells of Kindled Rats.

OBJECTIVE: Low-frequency stimulation (LFS) exerts suppressive effects in kindled animals. It is believed that overstimulated glutamatergic and decreased GABAergic transmission have long been associated with seizure activity. In this study, we investigated the effect of electrical LFS on different parameters of spontaneous excitatory and inhibitory post-synaptic currents (sEPSCs and sIPSCs) in hippocampal CA1 pyramidal cells in kindled animals. MATERIALS AND METHODS: In this experimental study, rats were kindled by electrical stimulation of the hippocampal CA1 area in a semi-rapid manner (12 stimulations/day). The animals were considered fully kindled when they showed stage 5 seizures on three consecutive days. One group of animals received LFS 4 times at 30 seconds, 6 hours, 18 and 24 hours following the last kindling stimulation. Each LFS consisted of 4 packages at 5 minutes intervals. Each package of LFS consisted of 200 pulses at 1 Hz and each monophasic square wave pulse duration was 0.1 millisecond. At 2-3 hours post-LFS, acute hippocampal slices were prepared and a whole cell patch clamp recording was performed in all animals to measure the different parameters of sEPSCs and sIPSCs. RESULTS: In kindled animals, the inter-event interval (as an index of occurrence) of sEPSCs decreased, whereas sIPSC increased. In addition, the decay time constant of sIPSCs as an index of the duration of its activity decreased compared to the control group. There was no significant difference in other parameters between the kindled and control groups. Application of LFS in kindled animals prevented the observed changes. There was no significant difference between the measured parameters in kindled+LFS and control groups. CONCLUSION: LFS application may prevent seizure-induced increase in the occurrence of sEPSCs and seizure-induced decrease in occurrence and activity duration of sIPSCs.

Effect of low frequency stimulation on impaired spontaneous alternation behavior of kindled rats in Y-maze test.

Epileptic seizures are characterized with cognitive disorders. In this study we investigated the effect of electrical low frequency stimulation (LFS), as a potential anticonvulsant agent, on kindled seizure-induced cognitive impairments. Animals were kindled through electrical stimulation of hippocampal CA1 area in a semi-rapid manner (12 stimulations/day). One group of animals received LFS 4 times at 0.5, 6.5, 24 and 30h following the last kindling stimulation. Applied LFS was consisted of 4 packages at 5min intervals. Each package contained 200 monophasic square wave pulses of 0.1ms duration at 1Hz. The Y-maze test was performed in all animals to measure the spontaneous alternation behavior. Kindled animals showed significant impairment in spontaneous alternation behavior compared to the control group. Application of LFS improved the observed impairment in spontaneous alternation behavior in kindled animals, so that there was no significant difference between kindled+LFS and control group. The observed improving effect of LFS was accompanied with a significant increase in calcineurin gene expression within the hippocampal area. Therefore, it may be postulated that application of LFS in kindled animals, which resulted in increment of calcineurin gene expression, can improve the seizure-induced impairment in spontaneous alternation behavior in Y-maze test.

Low-frequency electrical stimulation enhances the effectiveness of phenobarbital on GABAergic currents in hippocampal slices of kindled rats.

Low frequency stimulation (LFS) has been proposed as a new approach in the treatment of epilepsy. The anticonvulsant mechanism of LFS may be through its effect on GABAA receptors, which are the main target of phenobarbital anticonvulsant action. We supposed that co-application of LFS and phenobarbital may increase the efficacy of phenobarbital. Therefore, the interaction of LFS and phenobarbital on GABAergic inhibitory post-synaptic currents (IPSCs) in kindled and control rats was investigated. Animals were kindled by electrical stimulation of basolateral amygdala in a semi rapid manner (12 stimulations/day). The effect of phenobarbital, LFS and phenobarbital+LFS was investigated on GABAA-mediated evoked and miniature IPSCs in the hippocampal brain slices in control and fully kindled animals. Phenobarbital and LFS had positive interaction on GABAergic currents. In vitro co-application of an ineffective pattern of LFS (100 pulses at afterdischarge threshold intensity) and a sub-threshold dose of phenobarbital (100µM) which had no significant effect on GABAergic currents alone, increased the amplitude and area under curve of GABAergic currents in CA1 pyramidal neurons of hippocampal slices significantly. Interestingly, the sub-threshold dose of phenobarbital potentiated the GABAergic currents when applied on the hippocampal slices of kindled animals which received LFS in vivo. Post-synaptic mechanisms may be involved in observed interactions. Obtained results implied a positive interaction between LFS and phenobarbital through GABAA currents. It may be suggested that a combined therapy of phenobarbital and LFS may be a useful manner for reinforcing the anticonvulsant action of phenobarbital.

Enhancement of insulin-induced cutaneous vasorelaxation by exercise in rats: A role for nitric oxide and K(Ca2+) channels.

Insulin is a potent vasoactive hormone which induces vasodilatation at physiological concentrations. Aerobic exercise is known to improve insulin vasodilatory activity in humans and experimental animals. Since both insulin and physical training is known to activate K(ATP) and K(Ca2+) channels and increase nitric oxide (NO) synthesis, we hypothesized that insulin and exercise might use a common mechanism in mediating their vascular effect. The present study was carried out to investigate the role of NO, K(ATP) and K(Ca2+) channels in enhancement of insulin-induced cutaneous vasorelaxation by exercise in rats. Male Wistar rats were submitted to exercise training for 8weeks on a treadmill. Cutaneous microvascular response to insulin was recorded from soles skin using a laser Doppler flowmeter. Systemic arterial blood pressure and heart rate were measured using a tail-cuff during assessment of cutaneous blood flow. Subcutaneous injection of insulin induced a dose-dependent increase in skin blood flow in control rats which was significantly higher in exercised animals. Local inhibition of NO synthesis (l-NAME, 10(-4)M) was associated with a marked inhibitory effect on insulin-induced vasodilatation and this inhibition was significantly greater in exercised rats. Likewise, a selective K(Ca2+) channel blocker (iberiotoxin, 10(-9)M) inhibited insulin-induced vasodilatation and this inhibition was significantly exaggerated in exercised animals. Local K(ATP) blockade (glybenclamide, 10(-5)M) showed an identical response in sedentary and exercised animals. Insulin induced a marked vasodilatation in cutaneous microcirculation following aerobic exercise in rats. Both NO and K(Ca2+) channels might be involved in the genesis of this effect.