The role of HCN channels on the effects of T-type calcium channels and GABAA receptors in the absence epilepsy model of WAG/Rij rats.

In this study we used ivabradine (IVA), a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, to identify its effect on spike-wave discharges (SWDs); and aimed to determine the role of IVA on the effects of T-type calcium channel blocker NNC 55-0396, GABAA receptor agonist muscimol and antagonist bicuculline in male WAG/Rij rats. After tripolar electrodes for electrocorticogram (ECoG) recordings were placed on the WAG/Rij rats' skulls, 5, 10, and 20 mg/kg IVA were intraperitoneally administered for 7 consecutive days and ECoG recordings were obtained on days 0th, 3rd, 6th, and 7th for three hours before and after injections. While acute injection of 5, 10, and 20 mg/kg IVA did not affect the total number and the mean duration of SWDs, subacute administration (7 days) of IVA decreased the SWDs parameters 24 hours after the 7th injection. Interestingly, when IVA was administered again 24 hours after the 6th IVA injection, it increased the SWDs parameters. Western-blot analyses showed that HCN1 and HCN2 expressions decreased and HCN4 increased in the 5-month-old WAG/Rij rats compared to the 1-month-old WAG/Rij and 5-month-old native Wistar rats, while subacute IVA administration increased the levels of HCN1 and HCN2 channels, except HCN4. Subacute administration of IVA reduced the antiepileptic activity of NNC, while the proepileptic activity of muscimol and the antiepileptic activity of bicuculline were abolished. It might be suggested that subacute IVA administration reduces absence seizures by changing the HCN channel expressions in WAG/Rij rats, and this affects the T-type calcium channels and GABAA receptors.

The electrophysiological and behavioral evaluation of the peptide hemopressin and cannabinoid CB1 receptor agonist and antagonist in pentylenetetrazol model of epilepsy in rats.

This study endeavoured to assess the effect of hemopressin (Hp), a nano peptide obtained from the alpha chain of hemoglobin, on chronic epileptic activity and its potential correlation with cannabinoid receptor type 1 (CB1). Male Wistar albino rats (230-260 g) were used. The kindling process was conducted by administering a sub-convulsant dose of pentylenetetrazol (PTZ) (35 mg/kg, i.p) three times a week for a maximum of 10 weeks. Tripolar electrodes and external cannula guides for intracerebroventricular (i.c.v) injections were surgically implanted in the skulls of kindled rats. On the day of the experiment, doses of Hp, AM-251, and ACEA were administered prior to the PTZ injections. Electroencephalography recordings and behavioural observations were conducted simultaneously for 30 min after the PTZ injection. The administration of Hp (0.6 µg, i.c.v) resulted in a decrease in epileptic activity. The CB1 receptor agonist ACEA (7.5 µg, i.c.v) showed an anticonvulsant effect, but the CB1 receptor antagonist AM-251 (0.5 µg, i.c.v) displayed a proconvulsant effect. The co-administration of Hp (0.6 µg, i.c.v) and ACEA (7.5 µg, i.c.v) and of Hp (0.6 µg, i.c.v) and AM-251 (0.5 µg, i.c.v) produced an anticonvulsant effect. However, when AM-251 was administered prior to Hp, it produced a proconvulsant impact that overrode Hp's intended anticonvulsant effect. Interestingly, the co-administration of Hp (0.03 µg) + AM-251 (0.125 µg) unexpectedly exhibited an anticonvulsant effect. Electrophysiological and behavioural evaluations demonstrated the anticonvulsant effect of Hp in the present model, highlighting the possibility that Hp may act as an agonist for the CB1 receptor.

Differential effects of inhibitors of PTZ-induced kindling on glutamate transporters and enzyme expression.

Epilepsy is a neurological disorder resulting from abnormal neuronal firing in the brain. Glutamate transporters and the glutamate-glutamine cycle play crucial roles in the development of seizures. In the present study, the correlation of epilepsy with glutamate transporters and enzymes was investigated. Herein, male Wistar rats were randomly allocated into four groups (six animals/group); 35 mg/kg pentylenetetrazole (PTZ) was used to induce a kindling model of epilepsy. Once the kindling model was established, animals were treated for 15 days with either valproic acid (VPA, 350 mg/kg) or ceftriaxone (CEF, 200 mg/kg) in addition to the control group receiving saline. After treatment, electrocorticography (ECoG) was performed to record the electrical activity of the cerebral cortex. The glutamate reuptake time (T80 ) was also determined in situ using an in vivo voltammetry. The expression levels of glutamate transporters and enzymes in the M1 and CA3 areas of the brain were determined using a real-time polymerase chain reaction (RT-PCR). ECoG measurements showed that the mean spike number of the PTZ + VPA and PTZ + CEF groups was significantly lower (p < 0.05) than that of the PTZ group. Compared with the PTZ group, VPA or CEF treatment decreased the glutamate reuptake time (T80 ). The expression levels of EAAC1, GLT-1, GLAST, glutamine synthetase (GS), and glutaminase were increased in the PTZ group. Treatment with VPA or CEF enhanced the expression levels of GLT-1, GLAST, EAAC1, and GS, whereas the glutaminase expression level was reduced. The current results suggest that VPA or CEF decreases seizure activity by increasing glutamate reuptake by upregulating GLT-1 and GLAST expression, implying a possible mechanism for treating epilepsy. Also, we have suggested a novel mechanism for the antiepileptic activity of VPA via decreasing glutaminase expression levels. To our knowledge, this is the first study to measure the glutamate reuptake time in situ during the seizure (i.e., real-time measurement).

The effect of serotonin on penicillin-induced epileptiform activity.

OBJECTIVE: This study was aimed at examining the epileptiform activity of the 5-HT2 serotonin receptor agonist and antagonist, and 5-hydroxytryptophan (5-HTP) in penicillin-induced epilepsy in albino Wistar rats. METHODS: For this purpose, 90 albino male Wistar rats were used in this study. Epileptiform activity was induced by an injection of penicillin, an agonist of GABAA receptor, (500 IU, i.c.) into the somatomotor cortex. Thirty minutes after the injection of penicillin, 2,5-dimethoxy-4-iodoamphetamine (DOI, an agonist of 5-HT2 receptor) (0.5, 1, 2 and 4 mg/kg, i.p.), methysergide, an antagonist of 5-HT2 receptor, (1, 10, 20, 50 and 100 µM, i.c.v.) and 5-HTP, precursor of 5-HT, (25, 50, 75 and 100 mg/kg, i.p.) were administered, respectively. RESULTS: DOI, at the doses of 1 and 2 mg/kg, significantly decreased penicillin-induced epileptiform activity (p < 0.05). Methysergide, at the doses of 20, 50 and 100 µM, significantly increased the mean spike frequency of penicillin-induced epileptiform activity (p < 0.05). The doses of 50, 75 and 100 mg/kg of 5-HTP decreased the mean spike frequency of penicillin-induced epileptiform activity (p < 0.05). The mean of amplitude of penicillin-induced epileptiform activity did not significantly change in any of the groups (p > 0.05). CONCLUSION: The electrophysiological data from the present study suggest that serotonin 5-HT2 receptors have an important role in controlling penicillin-induced epileptiform activity in the rat.

Effects of Ginkgo biloba extract on brain oxidative condition after cisplatin exposure.

PURPOSE: The purpose of this study was to evaluate the efficacy of Ginkgo biloba extract (EGb 761) on oxidative events of brain in cisplatin-administrated rats. METHODS: Rats were divided into four experimental groups: 1) control (n=6); 2) cisplatin (8 mg/kg, intraperitoneally one dose, n=6); 3) EGb 761 (100 mg/kg intraperitoneally for 15 days, n=6); and 4) cisplatin + EGb 761 (n=6). After drug administration, rats were sacrificed and brain tissues were removed. Nitric oxide (NO), malondialdehyde (MDA) and glutathione (GSH) levels were evaluated in brain tissues. RESULTS: Single dose cisplatin administration significantly increased NO and GSH levels, but decreased MDA levels in brain tissue samples. EGb 761 treatment reversed the effects of cisplatin on NO and GSH levels, but did not affect the decreased MDA levels. CONCLUSION: Results of the study indicate that oxidative stress can be an important pathogenetic mechanism of cisplatin-induced neurotoxicity. EGb 761, an standardized extract of G. biloba leaves that has antioxidant properties, may improve the oxidative stress-related neurological side effects of cisplatin.

The effects of leptin and cannabinoid CB1 receptor agonist/antagonist in cerebral tissues of epileptic rats.

OBJECTIVE: In this study, the effects of leptin, cannabinoid-1 (CB1) receptor agonist ACEA and antagonist AM251, and the interactions between leptin and CB1 receptor agonist/antagonist on oxidant and antioxidant enzymes in the cerebrum, cerebellum, and pedunculus cerebri tissue samples were investigated in the penicillin-induced epileptic model. METHODS: Male Wistar albino rats (n=56) were included in this study. In anesthetized animals, 500 IU penicillin-G potassium was injected into the cortex to induce epileptiform activity. Leptin (1 µg), ACEA (7.5 µg), AM251 (0.25 µg), and the combinations of the leptin+ACEA and leptin+AM251 were administered intracerebroventricularly (i.c.v.) after penicillin injections. Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels were measured in the cerebral tissue samples and plasma with the ELISA method. RESULTS: MDA levels increased, while SOD and GPx levels decreased after penicillin injection in the cerebrum and cerebellum. The efficacy of penicillin on SOD, MDA and GPx levels was further enhanced after leptin or AM251 injections. Whereas, ACEA decreased the MDA levels and increased GPx levels compared with the penicillin group. Administration of AM251+leptin did not change any oxidation parameter compared with the AM251. Furthermore, co-administration of ACEA and leptin significantly increased oxidative stress compared with the ACEA-treated group by increasing MDA and decreasing GPx levels. CONCLUSION: It was concluded that leptin reversed the effect of ACEA on oxidative stress. Co-administration of AM251 and leptin did not change oxidative stress compared with the AM251-treated group suggesting AM251 and leptin affect oxidative stress using the same pathways.

The Effect of Chronic Swimming Exercise and Vitamin E Supplementation on Bone Element Metabolism in Epileptic Rats.

Introduction: This study aimed to investigate the effects of chronic swimming exercise and vitamin E administration on elemental levels in the bone tissue of epileptic rats. Methods: Forty-eight rats were divided into six groups: Control, Swimming, Swimming + vitamin E, Swimming + Epilepsy, Swimming + Epilepsy + vitamin E, and Epilepsy. Vitamin E was administered to the animals chronically by gavage at a dose of 500 mg/kg every other day for 3 months. Epileptiform activity was induced with penicillin in animals 24 hours after the last vitamin E intake. The exercise program consisted of daily 30-minute swimming sessions. At the end of the treatment period, the levels of calcium, chromium, copper, iron, magnesium, manganese, lead, and zinc (µg/gram tissue) in bone tissue samples were measured using an atomic emission device. Results: The results showed that all epileptic groups had significantly lower bone chromium levels compared to the control groups (p<0.05). The epileptic, and epileptic swimming groups had the lowest levels of bone calcium, magnesium, and zinc (p<0.05). Vitamin E administration resulted in a significant increase in bone calcium, magnesium, and zinc levels in the epileptic swimming group with vitamin E compared to the epileptic and epileptic swimming groups. (p<0.05). Conclusion: The findings of the study show that the administration of vitamin E improves calcium, magnesium, and zinc metabolism in the deteriorated bone tissue of the epileptic rat model.

Nesfatin­1 exerts anticonvulsant effect by reducing oxidative stress in experimental epilepsy model.

Neuropeptides play an important role in the pathogenesis of epilepsy. In the present study, the effect of nesfatin­1, a neuropeptide, was investigated on penicillin­induced epilepsy model. Epileptiform activity was induced by an injection of penicillin into the somatomotor cortex at 56 albino Wistar rats. Nesfatin­1 (i.c.v.) was administered at five different doses (12.5, 25, 50, 100, and 200 pmol) 30 min after a penicillin administration. Astressin 2B, a corticotropin­releasing factor (CRF) receptor antagonist, was administered 10 minutes later the effective dose of nesfatin­1 (50 pmol, i.c.v.). Superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR) and malondialdehyde (MDA) levels in cerebrum were analysed by ELISA method. Nesfatin­1, at the doses of 25, 50 and 100 pmol, significantly reduced the frequency of epileptiform activity. However, none of the doses of nesfatin­1 had any effect on the amplitude of epileptiform activity. Astressin 2B alone did not show any effect on epileptiform activity. In addition, astressin 2B had no effect on the anticonvulsant effect of nesfatin­1. Nesfatin­1 (at the doses of 25, 50, 100 pmol) did not alter SOD and GSH levels, but significantly increased the GPx and GR levels. Nesfatin­1 (at a dose of 50 pmol) significantly decreased the MDA level in the cerebrum. Nesfatin­1 shows anticonvulsant effect and astressin 2B did not affect the anticonvulsant effect of nesfatin­1. We suggest that nesfatin­1 has oxidative stress­mediated anticonvulsant effect in the penicillin­induced epileptic activity.

THE effect of general anesthetics on genetic absence epilepsy in WAG/Rij rats.

AIM: To establish safe and straightforward anesthesia used in experiments, we examined the effect of ketamine, ketamine/xylazine, urethane, chloral hydrate, pentobarbital, isoflurane, dexmedetomidine, and dexmedetomidine/ketamine on epileptiform activity in genetic absence epilepsy (WAG\Rij) rats. MATERIALS AND METHOD: Sixty-three male WAG/Rij rats weighing (170-190 g) were used. Tripolar electrodes were inserted into the skull. After ECoG activities were recorded for each animal for 2 hours as controls, , the anesthetic substances were administered and the recording continued for another 2 hours. All the anesthetic substances were administered intraperitoneally except isoflurane, which was administered by inhalation.The PowerLab system was used for electrophysiological activity recording and analysis. RESULTS: The administration of ketamine (90 mg/kg), ketamine/xylazine (90/10 mg/kg), urethane (1.25 g/kg), chloral hydrate (175 mg/kg), pentobarbital (50-90 mg/kg), isoflurane (induction 5%, maintaining 3-4%), dexmedetomidine (0.5-1 mg/kg), and dexmedetomidine/ketamine (50/90 mg/kg), significantly decreased the total number of SWD, the total number of spikes, and the SWD duration (p < 0,05). The mean duration of SWD was not affected in pentobarbital (50-90 mg/kg), isoflurane (induction 5%, maintaining 3-4%), dexmedetomidine (0.5-1 mg/kg), and Dexmedetomidine/ketamine (50/90 mg/kg) groups (p > 0.05). Time scale showed a significant decrease in the total number of SWD in the first 20 minutes (P < 0.001) for all groups except dexmedetomidine (0.5-1 mg/kg), and dexmedetomidine/ketamine (50/90 mg/kg) groups (p > 0.05). CONCLUSION: The anesthetics we used significantly reduced the epileptiform activity immediately after the administration, except dexmedetomidine and dexmedetomidine/ketamine groups, so we recommend using dexmedetomidine and Dexmedetomidine/ketamine in electrophysiological studies accompanied by anesthetics.

The Role of NMDA Receptors in the Effect of Purinergic P2X7 Receptor on Spontaneous Seizure Activity in WAG/Rij Rats With Genetic Absence Epilepsy.

P2X7 receptors (P2X7Rs) are ATP sensitive cation channels and have been shown to be effective in various epilepsy models. Absence epilepsy is a type of idiopathic, generalized, non-convulsive epilepsy. Limited data exist on the role of P2X7Rs and no data has been reported regarding the interaction between P2X7Rs and glutamate receptor NMDA in absence epilepsy. Thus, this study was designed to investigate the role of P2X7 and NMDA receptors and their possible interaction in WAG/Rij rats with absence epilepsy. Permanent cannula and electrodes were placed on the skulls of the animals. After the healing period of the electrode and cannula implantation, ECoG recordings were obtained during 180 min before and after drug injections. P2X7R agonist BzATP, at doses of 50 µg and 100 µg (intracerebroventricular; i.c.v.) and antagonist A-438079, at doses of 20 µg and 40 µg (i.c.v.) were administered alone or prior to memantine (5 mg/kg, intraperitoneal; i.p.) injection. The total number (in every 20 min), the mean duration, and the amplitude of spike-wave discharges (SWDs) were calculated and compared. Rats were decapitated and the right and left hemisphere, cerebellum, and brainstem were separated for the measurements of the advanced oxidation protein product (AOPP), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), glutathione peroxide (GPx), and glutathione reductase (GR). BzATP and A-438079 did not alter measured SWDs parameters, whereas memantine reduced them, which is considered anticonvulsant. BzATP did not alter the anticonvulsant effect of memantine, while A-438079 decreased the effect of memantine. Administration of BzATP increased the levels of SOD and GR in cerebrum hemispheres. A-438079 did not alter any of the biochemical parameters. Memantine reduced the levels of MDA, GSH, and GR while increased the level of CAT in the cerebrum. Administration of BzATP before memantine abolished the effect of memantine on MDA levels. The evidence from this study suggests that P2X7Rs does not directly play a role in the formation of absence seizures. P2X7Rs agonist, reduced the antioxidant activity of memantine whereas agonist of P2X7Rs reduced the anticonvulsant action of memantine, suggesting a partial interaction between P2X7 and NMDA receptors in absence epilepsy model.

The effects of intracerebroventricular AM-251, a CB1-receptor antagonist, and ACEA, a CB1-receptor agonist, on penicillin-induced epileptiform activity in rats.

PURPOSE: Several results support the conclusion that the cannabinoid system has a role in generation and cessation of epileptic seizures. The aim of this study was to evaluate the effects of intracerebroventricular AM-251 [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide], a CB1-receptor antagonist, and ACEA (arachidonyl-2-chloroethylamide), a CB1-receptor agonist, on penicillin-induced epileptiform activity in rats. METHODS: In the first set of experiments, 30 min after penicillin injection, AM-251, at doses of 0.125, 0.25, 0.5, and 1 µg, was administered intracerebroventricularly (i.c.v.). In the second set of experiments, 30 min after penicillin injection, ACEA, at doses of 2.5, 5, 7.5, and 15 µg (i.c.v.), was administered. In the third set of experiments, AM-251, at doses of 0.125 and 0.25 µg (i.c.v.), was administered 10 min before ACEA (7.5 µg, i.c.v.) injection. RESULTS: ACEA, at a dose of 7.5 µg, significantly decreased the frequency of penicillin-induced epileptiform activity without changing the amplitude. ACEA, at doses of 2.5, 5, and 15 µg, had no impact on either frequency or amplitude of epileptiform activity. AM-251, at doses of 0.25 and 0.50 µg, significantly increased the frequency of epileptiform activity. AM-251, at a dose of 0.25 µg (i.c.v.), was the most effective in changing the frequency of penicillin-induced epileptiform activity, and it also caused status epilepticus-like activity. AM-251, at doses of 0.125 and 0.25 µg, 10 min before ACEA (7.5 µg), reversed the anticonvulsant action of ACEA. DISCUSSION: The results of the present study provide electrophysiologic evidence for the role of CB1 receptors in regulating the frequency of epileptiform activity in the model of penicillin-induced epilepsy. To elucidate the precise mechanism of cannabinoid action in the brain during seizure, more advanced electrophysiologic and neurochemical studies are required.

The effect of alpha-tocopherol in the acute ethanol intake and its withdrawal on penicillin-induced epilepsy.

The present study was designed to investigate the influence of acute ethanol intake and its withdrawal on the anticonvulsant effect of alpha-tocopherol in penicillin-induced epileptiform activity. Ethanol-treated rats received a daily dose of 3 g/kg or 9.0 g/kg of 30% ethanol solution for 3 days. Thirty minutes after penicillin injection (500 units, i.c.) the most effective dose of alpha-tocopherol (500 mg/kg) was administered intramuscularly (i.m.). Acute administration of ethanol, in a dose of 3 g/kg, did not change either frequency or amplitude of penicillin-induced epileptiform activity, while dose of 9 g/kg ethanol significantly decreased the mean frequency of penicillin-induced epileptiform ECoG activity in the ethanol-treated group. Ethanol (9 g/kg) withdrawal also caused an increase in the amplitude of epileptiform ECoG activity in the withdrawal group. The results suggest that acute administration of high dose ethanol (9 g/kg) and alpha-tocopherol have some limited anticonvulsive effects in penicillin-induced epileptiform activity in rats.

Swimming exercise decreases the absence-like epileptic activity in WAG/Rij rats.

AIM: The aim of the present study was to evaluate the effects of long (60 min/day), moderate (30 min/day) and short (15 min/day) term daily swimming exercise programs for 90 days on durations and the spike-wave discharges (SWDs) seen in the electrocorticographic (ECoG) recordings of WAG/Rij rats with absence epilepsy. MATERIALS AND METHODS: Thirty-five adult male rats were divided into 5 groups as; Group 1: Control, Group 2: Sham (daily exposed to shallow water), Group 3: 15 min/day swimming exercise, Group 4: 30 min/day swimming exercise, Group 5: 60 min/day swimming exercise. After 90 days of swimming exercise program; ECoG recordings were taken for 2 h. Total number and cumulative length of SWDs in the recordings were used for evaluation of the seizures. RESULTS: Both of the SWD parameters were significantly decreased in all swimming exercise groups compared to control and sham groups. The moderate swimming group (30 min/day) was found the most effective exercise program considering both of the SWD parameters of absence epilepsy. CONCLUSION: The results of the present study provide electrophysiologic evidence for the role of swimming exercise on the modulation of genetic absence epilepsy seizures in WAG/Rij rats.

Effects of vitamin D and paricalcitol on epileptogenesis and behavioral properties of WAG/Rij rats with absence epilepsy.

AIM: Vitamin D (Vit D) has been considered as a neurosteroid and has a pivotal role in neuroprotection including epilepsy. Vit D regulator acts via a Vit D receptor (VDR). WAG/Rij rats have a genetically epileptic model of absence epilepsy with comorbidity of depression. The aim of the present study was to investigate the effect of Vit D and paricalcitol (PRC) on WAG/Rij rats. MATERIAL AND METHODS: Sixty-three male WAG/Rij rats and seven male Wistar rats were used. The effects of acute and chronic treatment with Vit D (5.000 and 60.000 IU/kg, i.p) and PRC (0.5, 5 and 10 µg/kg, i.p) on absence seizures, and related psychiatric comorbidity were investigated in WAG/Rij rats. Depression-like behavior was assayed by using the forced swimming test (FST) and; anxiety-like behavior by using the open field test (OFT). RESULTS: Acute Vit D treatments (5.000 and 60.000 IU/kg) similarly reduced the number and duration of spike-wave discharges (SWDs) and showed anxiolytic-antidepressive effect whereas there were no significant changes in other measured parameters between the daily and the bolus dose of Vit D. Acute administration of PRC (0.5, 5 and 10 µg/kg) showed anti-convulsive and anxiolytic-antidepressive effect. The dose (0.5 µg/kg) of PRC was the most effective dose. Chronic treatment was more effective than acute therapy in all parameters. CONCLUSION: The results of the present study demonstrate that Vit D and PRC have antiepileptic and anxiolytic-antidepressive effects on the absence epilepsy in WAG/Rij rats.

The interaction between P2X7Rs and T-type calcium ion channels in penicillin-induced epileptiform activity.

Limited information exists on the link between purinergic class P2X7 receptors (P2X7Rs) and calcium ion channels in epilepsy; no data has been reported regarding the interaction between P2X7Rs and T-type calcium ion channels in epilepsy. Thus, this study is an evaluation of the role that T-type calcium ion channels play in the effect of P2X7Rs on penicillin-induced epileptiform activity. In the first set of experiments, P2X7R agonist BzATP (at 25-, 50-, 100- and 200-µg doses), P2X7R antagonist A-438079 (at 5-, 10-, 20- and 40-µg doses) and T-type calcium ion channel antagonist, NNC-550396 were administered for electrophysiological analyses 30 min after penicillin injection (2.5 µl, 500 IU). In the second set of experiments, the effective doses of these substances were used for biochemical analyses. Malondialdehyde (MDA), advanced oxidation protein product (AOPP), glutathione (GSH), glutathione reductase (GR), glutathione peroxide (GPx), catalase (CAT) and superoxide dismutase (SOD) levels were measured in the cerebrum, cerebellum and brainstem of rats. BzATP (100 µg, icv) increased the mean frequency of epileptiform activity, whereas A-438079 (40 µg, icv) and NNC-550396 (30 µg, ic) reduced it. Both A-438079 and NNC-550396 reversed BzATP's proconvulsant action. BzATP increased lipid peroxidation and protein oxidation; it also altered other antioxidant enzymes measured in this study, which were all then reversed via A-438079 and NNC-550396, at least in the cerebrum. The electrophysiological and biochemical analysis of present study suggest that P2X7Rs and its interaction with T-type calcium ion channels play an important role in the experimental model of epilepsy.

The effects of moderate running exercise and L-tyrosine on penicillin-induced epileptiform activity in rats.

Regular exercise and amino acid supplementation, popular approaches toward the reduction of epileptic seizures, have been extensively researched. This study was conducted to evaluate the effects of treadmill exercise and L-tyrosine treatment on the frequency and amplitude of epileptiform activity in rats. A total of 32 male albino Wistar rats were randomly divided into four groups: control, exercise, L-tyrosine, and exercise + L-tyrosine. L­tyrosine was supplemented by oral gavage (500 mg/kg/day, 2.5 mL solution). The treatments were performed 5 days a week for 10 weeks. The rats were anesthetized and then administered 500 IU penicillin into the left cerebral cortex using a microinjector and electrocorticogram (ECoG) activity was recorded for 3 hours using a Power Lab data acquisition system. The frequency and the amplitude of the ECoG recordings were analyzed offline. Compared to the control group, spike frequency decreased significantly in all other groups. There was no statistically significant difference between the groups in terms of spike amplitude and latency. In this study, the effects of regularly administered treadmill exercise and L-tyrosine use on epileptiform activity were examined and evaluated together for the first time. The results of this study showed that regular exercise and L-tyrosine use decreased epileptiform activity. Further research and clinical trials are needed to investigate the extent to which L-tyrosine and physical activity interfere with the epileptic state by investigating different doses of L-tyrosine and different severity/ time/type of exercise protocols.

The effect of autogenous vein grafts on nerve repair with size discrepancy in rats: an electrophysiological and stereological analysis.

Aside from anatomical repairs, the reestablishment of sensory and motor innervations for proper functional recovery is one of the fundamental objectives of reconstructive surgery. The heterotopic transfer of autologous tissues is likely to result in a size discrepancy between the donor and recipient nerves, which will have a negative influence on regeneration. Twenty Wistar albino female rats were used in a study that was divided into two main groups: tibial-peroneal (TP) and peroneal-tibial repair (PT). Both types of nerves were exposed on the hind legs with the nerves cut on the right side, while the proximal stump of the tibial nerve and distal stump of the peroneal nerve were sutured to each other. These groups are also called end-to-end neurorrhaphy groups (EtoE). On the left side, the tibial and peroneal nerves were cut on the same level as on the right side. After the end-to-end epineural suturing of the nerve, the vein graft was slid over to the repair zone under irrigation. These are called the vein graft group (VG). All processes mentioned above were also done for the PT group. On the 90th postoperative day, anesthetized animals were fixed prone on a board, with the nerves carefully dissected for electrophysiological recording. Stereological methods for an estimation of the total number of myelinated fiber, a mean axonal cross-section area and the thickness of the myelin sheet were used. In TP and PT groups, nerve conduction velocities were found to be higher within the VG group. Nevertheless; the difference was only significant in the PT group. In both TP and PT groups, the increase in the axon number, axon area and myelin thickness were statistically different in favor of the vein graft sides. An appearance of vacuoles and degenerated pertinacious material within the myelin sheath of EtoE sides was seen. A histomorphological examination of the sections proximal to, from, and distal to the repair zone over three months revealed less epineural scarring, a thinner epineurium, more regenerated axons and fewer inflammatory cells in groups where vein grafting was used, because the vein graft provided additional mechanical and chemical support in the size discrepancy of the nerve regeneration.

Sexual dimorphism in the medial vestibular nucleus of adult rats: stereological study.

The vestibular system helps the body to maintain equilibrium. There are four vestibular nuclei on the right and left sides, the medial vestibular nucleus being the largest. The volumes and total numbers of neurons in the left and right medial vestibular nuclei of adult male and female rats were estimated using stereological techniques. The volumes of the left and right medial vestibular nucleus were 0.67 +/- 0.03 mm3 and 0.71 +/- 0.02 mm3 in the female, and 0.55 +/- 0.02 mm3 and 0.61 +/- 0.03 mm3 in the male rats, respectively. Total neuron numbers in the left and right medial vestibular nuclei were 19.364 +/- 791 and 20.978 +/- 784 in the female, and 16.905 +/- 229 and 15.547 +/- 439 in the male rats, respectively. No asymmetry in volume was found between the left and right sides in either sex; but a significant difference in volume was observed for the right medial vestibular nucleus between male and female rats. A significant difference in total neuron number between the left and right medial vestibular nuclei was observed in female and male rats: in male rats, left > right; in female rats, right > left. There was also a significant difference between male and female rats with regard to total number of neurons in the medial vestibular nuclei, the female having more neurons than the male on both sides, that is, female > male. These results indicate that neuron number in the medial vestibular nucleus shows laterality in the same sex, and a female-based sexual dimorphism.

The involvement of nitric oxide in the anticonvulsant effects of alpha-tocopherol on penicillin-induced epileptiform activity in rats.

A variety of animal seizure models exist which help to document the effects of alpha-tocopherol (Vitamin E) and specify its action. In the present study, we provide further evidence for the functional involvement of NO in the anticonvulsant effects of alpha-tocopherol on penicillin-induced epileptiform electrocorticographical (ECoG) activity in rats. The epileptiform ECoG activity was induced by microinjection of penicillin into the left sensorimotor cortex. Thirty minutes after penicillin injection, the most effective dose of alpha-tocopherol (500 mg/kg) was administrated intramuscularly (i.m.). Alpha-tocopherol decreased the frequency of penicillin-induced epileptiform ECoG activity without changing the amplitude. The effect of systemic administration of nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) and NO substrates, L-arginine and sodium nitro prusside (SNP) on anticonvulsive effects of alpha-tocopherol was investigated. The administration of L-NAME (60 mg/kg, i.p.) did not influence the frequency of epileptiform ECoG activity while administration of L-arginine (500 mg/kg, i.p.) and SNP (6 mg/kg, i.p.) significantly decreased in the penicillin-treated group. The administration of L-NAME (60 mg/kg, i.p.) 10 min after alpha-tocopherol (500 mg/kg, i.m.) application reversed the anticonvulsant effects of alpha-tocopherol. The administration of L-arginine (500 mg/kg, i.p.) and SNP (6 mg/kg, i.p.) did not affect the frequency of epileptiform ECoG activity in alpha-tocopherol supplemented group. L-arginine and SNP did not provide an additional anticonvulsant effect in alpha-tocopherol supplemented group. These results support the involvement of the nitric oxide pathway in the anticonvulsant effect of alpha-tocopherol on the penicillin-induced epileptiform ECoG activity.

The role of nitric oxide in the anticonvulsant effects of pyridoxine on penicillin-induced epileptiform activity in rats.

The present study was conducted to identify the role of nitric oxide (NO) in the anticonvulsant effects of pyridoxine hydrochloride on penicillin-induced epileptiform activity in rats. A single microinjection of penicillin (500 units) into the left sensorimotor cortex induced epileptiform activity within 2-4 min, progressing to full seizure activity lasting about 3-5h. Thirty minutes after penicillin injection, 20, 40, 80, and 160 mg/kg of pyridoxine hydrochloride was administered intraperitoneally (i.p.). Pyridoxine significantly reduced the frequency of penicillin-induced epileptiform activity. A low dose of pyridoxine (40 mg/kg) was the most effective in reducing both the frequency and amplitude of epileptiform activity. The effect of systemic administration of nitric oxide synthase (NOS) inhibitors, non-selective N(G)-nitro-L-arginine methyl ester (L-NAME), selective neuronal NOS inhibitor, 7-nitroindazole (7-NI) and NO substrate, L-arginine on anticonvulsive effects of pyridoxine was investigated. The administration of L-arginine (500 mg/kg, i.p.) and 7-NI (25 and 50 mg/kg, i.p.) significantly decreased the frequency of epileptiform electrocorticographical (ECoG) activity while administration of L-NAME (60 mg/kg, i.p.) and the inactive form of arginine (D-arginine) did not influence it. The administration of L-NAME (60 mg/kg, i.p.) 15 min before pyridoxine (40 mg/kg i.p.) application reversed the anticonvulsant effects of pyridoxine whereas 7-NI (25 and 50 mg/kg, i.p.) did not influence it. The same dose of its inactive enantiomer N(G)-nitro-D-arginine methyl ester (d-NAME) failed to reverse the anticonvulsant effects of pyridoxine. The administration of L-arginine (500 mg/kg, i.p.) did not affect the frequency of epileptiform ECoG activity in the pyridoxine administered group. L-arginine did not reverse the anticonvulsant effect of 7-NI in the penicillin and pyridoxine administered groups. The results of present study indicate that the inhibitory effect on the anticonvulsant activity of pyridoxine against penicillin-induced epileptiform activity was produced by L-NAME, not by 7-NI, and is probably not related to the decrease of NOS activity in the brain.