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1.
The time course of the effect of pentylenetetrazol (PTZ)-induced kindling on acetylcholine release in the hippocampus of freely moving rats was investigated with the transversal microdialysis technique. The basal extracellular concentration of acetylcholine in the hippocampus was reduced significantly (−29%, P<0.05) after 3 weeks, and the effect was maximal (−52%, P<0.01) after 4 weeks and remained essentially unchanged during the remaining 4 weeks of PTZ treatment (30 mg/kg, i.p., 3 times/week), relative to vehicle-treated rats. The basal release of acetylcholine in the prefrontal cortex and in the striatum of kindled rats was unchanged compared with that of vehicle-treated rats. The specific binding of [3H]quinuclidinyl benzilate, a non-selective ligand of muscarinic receptors, was significantly increased (+29%, P<0.01) in hippocampal membranes, but not in membranes prepared from the prefrontal cortex or striatum, of PTZ-kindled rats. Thirty days after discontinuation of PTZ treatment, both hippocampal acetylcholine output and the density of muscarinic receptors had returned to values characteristic of vehicle-treated rats, whereas seizure susceptibility did not differ significantly from that apparent 4 days after PTZ administration. These results suggest that the selective and transient decrease in acetylcholine output and the parallel increase in the density of postsynaptic muscarinic receptors in the hippocampus may play a role in facilitating the development of kindling rather than in the maintenance of the kindled state. © 1997 Elsevier Science B.V. All rights reserved.  相似文献   

2.
Multiple lines of investigations have explored the role of cyclooxygenases (COX) in epilepsy and related neuropsychiatric disorders. Cyclooxygenase particularly, COX-2 expression was found to increase in brain during seizure paradigms. The present study was carried out to investigate the effect of rofecoxib, a selective COX-2 inhibitor against pentylenetetrazol (PTZ i.v.) seizure threshold in mice. The study was further extended to elucidate the possible involvement of adenosinergic mechanism in mediating its anticonvulsant action. Minimal dose of PTZ (i.v., mg/kg) needed to induce different phases (myoclonic jerks, generalized clonus and tonic extension) of PTZ convulsions were noted as an index of seizure threshold. Acute administration of rofecoxib (4mg/kg, i.p.) before PTZ infusion produced an elevation of seizure threshold for all the phases of convulsions. A lower dose of rofecoxib (2mg/kg, i.p.) showed an increase in PTZ seizure threshold for the onset of myoclonic jerks and tonic extension phases but not for generalized clonus. A still lower dose of rofecoxib (1mg/kg, i.p.) failed to increase the threshold in any of the convulsive phases induced by PTZ i.v. infusion. Pretreatment with sub-effective dose of rofecoxib (1mg/kg, i.p.) enhanced the action of sub-protective doses of either adenosine (25mg/kg, i.p.) or 2-chloroadenosine (1 or 2mg/kg, i.p.) in increasing the seizure threshold. On the contrary, treatment with caffeine (100 or 200mg/kg, i.p.) or theophylline (50 or 100mg/kg, i.p.), both non-selective A(1)/A(2) adenosine receptor antagonists reversed the anticonvulsant effect of rofecoxib (4mg/kg, i.p.). Further, dipyridamole (5mg/kg, i.p.), an adenosine uptake inhibitor displayed an anticonvulsant effect with rofecoxib (1mg/kg, i.p.). The study for the first time demonstrated the possible involvement of adenosinergic system in the anticonvulsant effects of rofecoxib against PTZ i.v. seizure threshold paradigm in mice.  相似文献   

3.
The present study investigated the effects of Naringin on seizure severity, progress of kindling, memory impairment, oxidative stress, neurochemicals, and neural damage in Pentylenetetrazole (PTZ)-induced kindling. Alternate intra-peritoneal injections of PTZ induced kindling at 22 injections of PTZ. In comparison with the PTZ group, pretreatment with Naringin 30 min prior to PTZ administration and on a PTZ-free day was found to lead to a decreased seizure score, a mitigated progress of kindling, decreased transfer latency, and increased total number of arm entries, % alternation behavior in Y maze, and % conditioned avoidance response in a pole climbing apparatus. Biochemical analysis of the frontal and temporal cortexes and the hippocampus of the brain showed that Naringin attenuated the level of lipid peroxidation (MDA) and augmented the reduced glutathione, superoxide dismutase, catalase, and total thiol results in decreased oxidative stress compared with the PTZ group and control group. Investigation of neurochemicals revealed a minute change in gamma amino butyric acid (GABA), glutamate and dopamine, and decreased AChE in the three regions. Increased CA1 neuronal density in the hippocampus and increased cell density in the frontal and temporal regions indicate the potential of naringin to act against PTZ-induced kindling, memory impairment, oxidative stress, neurochemical changes, and histological aberrations.  相似文献   

4.
GFAP和Fos蛋白在戊四氮致痫大鼠前脑中的表达变化   总被引:2,自引:0,他引:2  
目的 研究大鼠在戊四氮导致癫痫发作时前脑内星形胶质细胞和神经元的形态学反应及其相互关系。方法 应用免疫组织化学单标记法分别显示前脑内GFAP和Fos蛋白表达的时间规律,并用免疫组织化学双重标记显示GFAP和Fos蛋白表达的相互关系。结果 在戊四氮导致大鼠癫痫发作早期,前脑的星形胶质细胞被激活,细胞体积增大,突起粗大,GFAP表达阳性,随着存活时间的变化,星形胶质细胞的反应经历先逐渐升高后降低的过程。被激活的星形胶质细胞和神经元表达Fos蛋白阳性,也呈现逐渐升高又降低的变化;另外,GFAP阳性星形胶质细胞和Fos阳性神经元在前脑主要分布在大脑皮层、海马、杏仁核等部位,二者的分布特征基本一致。结论 星形胶质细胞可能和神经元一起参与了戊四氮所致癫痫发作的变化。  相似文献   

5.
The effects of pentylenetetrazol (PTZ)-induced kindling on the activity of mesocortical, mesoaccumbens, and nigrostriatal dopaminergic neurons was investigated with the transversal microdialysis technique in freely moving rats. Four days after the last chronic administration of PTZ, the basal extracellular concentrations of dopamine in the prefrontal cortex, nucleus accumbens, and striatum of kindled rats were significantly increased (+76, +36, +49%, respectively) relative to those of animals chronically treated with saline. Moreover, dopamine output was markedly more sensitive to the effect of a challenge injection of PTZ (20 mg/kg ip) in the prefrontal cortex (+93 vs. +50%, relative to basal values), the nucleus accumbens (+36 vs. +4%), and the striatum (+50 vs. +35%) of kindled rats relative to that in the control animals. Because kindled rats and their controls are habituated to handling, the neurochemical mechanisms that underlie the effects of chemical kindling on the sensitivity of dopaminergic neurons to PTZ were investigated by comparing the effects of an acute administration of PTZ (20 mg/kg ip) between naive and handling-habituated animals. The sensitivity of dopamine output to PTZ in naive rats was markedly greater than that in handling-habituated animals for the prefrontal cortex (+83 vs. +50%) and nucleus accumbens (+35 vs. +4%), but not for the striatum (+35 vs. +32%). These results indicate that PTZ kindling enhances the basal activity and the sensitivity to PTZ of dopamine neurons in rat brain and suggest that mesocortical, mesoaccumbens, and nigrostriatal dopaminergic neurons contribute to the central alterations associated with experimental epilepsy. Synapse 26:351–358, 1997. © 1997 Wiley-Liss Inc.  相似文献   

6.
7.
To investigate the role of non-NMDA receptors in epileptic seizures, we examined the antiepileptogenic and anticonvulsant effects of NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)-quinoxaline), a potent and selective AMPA receptor antagonist, in the rat kindling model. Systemic administration of 10–40 mg/kg NBQX significantly and dose dependently suppressed previously kindled seizures from the amygdala (AM), assessed in terms of the motor seizure stage and afterdischarge (AD) duration. The maximal effects were observed at 0.5–1 h after drug injection. When the intensity of electrical stimulation was increased to twice the generalized seizure-triggering threshold (GST), the anticonvulsant effects of NBQX on AM-kindled seizures were not reversed, suggesting that the effects were not due to non-specific elevation of the GST. In contrast to AM-kindled seizures, 20–40 mg/kg NBQX significantly suppressed only the motor seizure stage without reducing the AD duration of previously hippocampal-kindled seizures. Daily administration of 15 or 30 mg/kg NBQX prior to each electrical stimulation of the AM markedly and significantly suppressed the development of kindling. During drug sessions, the growth of the AD duration was blocked almost completely, while the waveform of ADs became more complex. These results indicate that NBQX has potent antiepileptogenic and anticonvulsant actions on kindling, at least more from the AM and that non-NMDA receptors have an important role in seizure propagation.  相似文献   

8.
This experiment examined and compared the effects of pre-test administration of a selective COX-2 inhibitor (celecoxib), at the doses in the range of mg/kg and ng/kg on morphine state-dependent learning in step-down passive avoidance task in mice. Pre-training administration of 5mg/kg of morphine-impaired memory retrieval tested 24h later, which was restored by pre-test administration of the same dose of the drug. Pre-test administration of celecoxib (12.5, 25 and 50mg/kg), alone or in combination with morphine (1mg/kg) prevents morphine-induced memory impairment. Ultra-low doses (ULDs) of celecoxib (2, 10 and 50 ng/kg) produced no change in morphine-induced memory impairment. However, co-administration of nanogram doses of celecoxib with 5mg/kg of morphine in the test day prevented morphine-induced memory improvement, an action different from mg/kg doses. These findings implicate the involvement of COX-2 in memory retrieval and demonstrate that the effect of celecoxib ULD is different from that of mg/kg doses.  相似文献   

9.
10.
Monoamine oxidase (MAO) inhibitors were the first antidepressant drugs to be prescribed and are still used today with great success, especially in patients resistant to other antidepressants. In this study, we evaluated the MAO inhibitory properties and the potential antidepressant action of 2-(3,4-dimethoxy-phenyl)-4,5-dihydro-1H-imidazole (2-DMPI) in mice. We found that 2-DMPI inhibited both MAO isoforms (K(i) values were 1.53 (1.3-1.8) μM and 46.67 (31.8-68.4) μM for MAO-A and MAO-B, respectively) with 30-fold higher selectivity toward MAO-A. In relation to the nature of MAO-A inhibition, 2-DMPI showed to be a mixed and reversible inhibitor. The treatment with 2-DMPI (100-1000 μmol/kg, s.c.) caused a significant decrease in immobility time in the tail suspension test (TST) without affecting locomotor activity, motor coordination or anxiety-related activities. Conversely, moclobemide (1000 μmol/kg, s.c.) caused a significant increase in immobility time in the TST, which appeared to be mediated by a nonspecific effect on motor coordination function. 2-DMPI (300 μmol/kg, s.c.) decreased serotonin turnover in the cerebral cortex, hippocampus and striatum, whereas dopamine turnover was diminished only in the striatum, and norepinephrine turnover was not changed. The antidepressant-like effect of 2-DMPI was inhibited by the pretreatment of mice with methysergide (2 mg/kg, s.c., a non-selective serotonin receptor antagonist), WAY100635 (0.1 mg/kg, s.c., a selective 5-HT(1A) receptor antagonist) or haloperidol (0.05 mg/kg, i.p., a non-selective dopamine receptor antagonist). These results suggest that 2-DMPI is a prototype reversible and preferential MAO-A inhibitor with potential antidepressant activity, due to its modulatory effect on serotonergic and dopaminergic systems.  相似文献   

11.
Consumption of caffeine, an adenosine receptor antagonist, was found to be inversely associated with the incidence of Alzheimer's disease. Moreover, caffeine protects cultured neurons against beta-amyloid-induced toxicity, an effect mimicked by adenosine A(2A) but not A(1) receptor antagonists. We now tested if caffeine administration would prevent beta-amyloid-induced cognitive impairment in mice and if this was mimicked by A(2A) receptor blockade. One week after icv administration of the 25-35 fragment of beta-amyloid (Abeta, 3 nmol), mice displayed impaired performance in both inhibitory avoidance and spontaneous alternation tests. Prolonged treatment with caffeine (1 mg/ml) had no effect alone but prevented the Abeta-induced cognitive impairment in both tasks when associated with acute caffeine (30 mg/kg) 30 min treatment before Abeta administration. The same protective effect was observed after subchronic (4 days) treatment with daily injections of either caffeine (30 mg/kg) or the selective adenosine A(2A) receptor antagonist SCH58261 (0.5 mg/kg). This provides the first direct in vivo evidence that caffeine and A(2A) receptor antagonists afford a protection against Abeta-induced amnesia, which prompts their interest for managing Alzheimer's disease.  相似文献   

12.
In the present study, neuroprotective effect of 4-amino-1,8-napthalimide (4-ANI), a poly(ADP-ribose) polymerase (PARP) inhibitor was investigated in middle cerebral artery occlusion (MCAo)-induced focal ischemia. Sprague-Dawley rats were subjected to 2 h of middle cerebral artery occlusion followed by 22 h of reperfusion. After 22 h of reperfusion rats were evaluated for cerebral infarction, neurological deficits, brain NAD levels, and in situ terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL). Focal ischemia produced significant infarct volume (201 +/- 14 mm3), neurological scores (2 +/- 0.5) and 28 +/- 4.5% brain NAD depletion. Ischemia was associated with increased in TUNEL positive cells in brain sections indicating DNA fragmentation. 4-ANI treatment (1 and 3 mg/kg, i.p.) significantly decreased infarct volume to 35 +/- 7% and 70 +/- 6%, respectively. Neurological functions were also significantly improved at these doses. 4-ANI (3 mg/kg) completely reversed brain NAD depletion and significantly reduced the increase in the number of TUNEL positive cells. Nevertheless, 4-ANI treatment did not alter cerebral blood flow and blood pressure. Our study suggests 4-ANI is a potent neuroprotective agent in focal cerebral ischemia and its neuroprotective effects may be attributed to reduction of NAD depletion and DNA fragmentation.  相似文献   

13.
Parkinson's disease (PD) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity are both associated with dopaminergic neuron death in the substantia nigra. Although a variety of evidence has shown that degenerative cells have apoptotic features, the role of apoptosis in disease pathology remains controversial. The 1-methyl-4-phenylpyridinium ion (MPP(+)), a metabolite of MPTP, was recently shown to alter the expression of proteins involved in translational control. The initiation step of translational control is regulated by a cascade of phosphorylation affecting proteins of the antiapoptotic way controlled by mammalian target of rapamycin (mTOR) and of the proapoptotic way controlled by double-stranded RNA protein-dependent kinase (PKR). A study showed that MPP(+) induced an increase in eIF2alpha phosphorylation, leading to inhibition of protein synthesis. The aims of our study were: (1) to assess the effects of MPP(+) toxicity on molecular factors of PKR and mTOR signaling pathways in murine neuroblastoma cells, and (2) to examine the ability of VIP and PACAP peptides to counteract the MPP(+) toxicity. Our findings showed that MPP(+) induced phosphorylation of eIF2alpha and significantly reduced the expression of phosphorylated mTOR, p70S6K, eIF4E, and 4E-BP1, suggesting its toxicity in controlling protein synthesis. Furthermore, the VIP peptide had no effect on either the PKR or the mTOR signaling pathway. On the contrary, the PACAP 27 neuropeptide prevented MPP(+)-induced eIF2alpha phosphorylation and blocked MPP(+) toxicity in molecular factors of the mTOR pathway. And last, PACAP 27 seemed to protect Neuro-2a cells from the apoptotic process as assessed by the decreased nuclear condensation after DAPI staining. These results could open new paths of research of PACAP in PD.  相似文献   

14.
Apamin, a highly selective and potent peptide that blocks the SKCa-channels has been suggested to be a cognition enhancer. We tested apamin in the Morris water escape task, in shock motivated avoidance tasks, and in operant tasks in the Skinnerbox. We also used non-cognitive tests, such as the rat forced swimming test and cocaine-induced locomotor activity in the open field, and a test to assess the side effect profile. Mice and rats from different strains, and rats of different ages were used. The rat studies provided only weak support for the notion that apamin acts as a cognition enhancer. More convincing evidence was obtained from the mouse studies. Overt side effects of apamin were found at the dose of 0.3 mg kg−1. This dose was close to, or even overlapped, the doses which improved cognition in mice. We conclude that apamin is a poor tool to assess the role of SKCa-channels in learning and memory processes.  相似文献   

15.
Feretia apodanthera Del. (Rubiaceae) is extensively used in ethnomedicine in Cameroon and Nigeria for epilepsy, febrile convulsions, and rheumatic pains and for enhancing cognitive performance. The aim of the present study was to examine the effects of a lyophilized aqueous extract of F. apodanthera on the course of kindling development, kindling-induced learning deficit, oxidative stress markers, and cholinesterase activity in pentylenetetrazole (PTZ)-kindled mice. Pentylenetetrazole, 30 mg/kg, induced kindling in mice after 30.00 ± 1.67 days. The aqueous extract of F. apodanthera showed dose-dependent antiseizure effects. Feretia apodanthera (150–200 mg/kg) significantly increased the latency to myoclonic jerks, clonic seizures, and generalized tonic–clonic seizures. The extract also improved the seizure score and decreased the number of myoclonic jerks. Pentylenetetrazole kindling induced significant oxidative stress and cognitive impairment which were reversed by pretreatment with F. apodanthera in a dose-dependent manner. The significant decrease in cholinesterase activity observed in the PTZ-kindled mice was reversed by pretreatment with the F. apodanthera extract. The results indicated that pretreatment with the aqueous extract of F. apodanthera antagonizes seizures, oxidative stress, and cognitive impairment in PTZ-kindled mice. The aqueous extract of F. apodanthera also showed anxiolytic activities, but the inhibition of memory impairment was not attributed to the anxiolytic activities of the plant. These results thus suggest the potential of F. apodanthera as an adjuvant in epilepsy both to prevent seizures as well as to protect against seizure-induced oxidative stress and memory impairment.  相似文献   

16.
目的探讨神经节细胞胶质瘤的临床表现、影像学特点、治疗方法及预后。方法回顾性分析18例神经节细胞胶质瘤患者的临床表现、影像学特点、治疗方法及随访结果。结果所有患者均行手术治疗,肿瘤全切16例,次全切除2例,复发1例,再次手术治疗。所有病例术后均随访2-6年,16例恢复正常工作和学习;14例术后癫痫缓解,3例需要服用药物控制癫痫。1例3年后复发,二次手术后恢复正常。结论神经节细胞胶质瘤预后相对良好,手术是目前其主要的治疗方法,早期发现,早期治疗,有助于提高患者生存质量和减少复发率。  相似文献   

17.
Various inhibitors of nitric oxide synthase (NOS) have been shown to possess antidepressant- and anxiolytic-like properties in animal models. The aim of this study was to compare the behavioural effects of NOS inhibitor 7-nitroindazole (7-NI) with the more selective neuronal NOS inhibitor 1-(2-trifluoromethylphenyl)imidazole (TRIM) in animal models predictive of antidepressant- and anxiolytic-like activity in order to clarify the role of distinct isoforms of NOS in the regulation of depression and anxiety. Both TRIM (50 mg/kg) and 7-NI (50 mg/kg) decreased the immobility time in the forced swimming test. The magnitude of the effect was comparable to that of the tricyclic antidepressant imipramine (15 mg/kg). The antidepressant-like effect of TRIM was counteracted by pretreatment with L-arginine (250 mg/kg). The systemic administration of TRIM (50 mg/kg), but not 7-NI (up to 50 mg/kg) increased the time spent in the light side of the apparatus in the light-dark compartment test. The anxiolytic-like effect of TRIM was antagonised by pretreatment with L-arginine. Both TRIM and 7-NI decreased the locomotion of animals in the open field and caused motor incoordination on rotarod. These motor side effects were more pronounced in the case of 7-NI and were not diminished by pretreatment with L-arginine. We conclude that neuronal NOS seems to play the key role in the antidepressant- and anxiolytic-like effects of NOS inhibitors.  相似文献   

18.
Muscimol, 0.25-1.0 mg/kg, i.v., was administered acutely to 4 adolescent baboons, Papio papio, that show photically induced epilepsy. On the EEG, slowing of background rhythms was associated with the appearance of spikes, polyspikes, and recurring symmetrical spike-wave complexes. These changes were maximal 0.5-2 hr after muscimol injection. Regular testing with intermittent light stimulation showed either no change from control responses or a more severe epileptiform EEG 0.1-3 hr after muscimol. Photically induced myoclonus was not modified by muscimol. Despite its GABA-abonist properties, muscimol is not an effective anticonvulsant.  相似文献   

19.
PURPOSE: The purpose of this study was to test the teratogenic potential of the antiepileptic drug (AED) levetiracetam (LEV), its major metabolite in humans, 2-pyrrolidone-N-butyric acid (PBA), and enantiomer, (R)-alpha-ethyl-oxo-pyrrolidine acetamide (REV), in a well-established mouse model. METHODS: All compounds were administered by intraperitoneal injections once daily to SWV/Fnn mice on gestational days 8-1/2 to 12-1/2. LEV was administered at doses of 600, 1,200, and 2,000 mg/kg/day, piracetam (PIR) and PBA, at 600 and 1,200 mg/kg/day, and REV, at 600 mg/kg/day. On gestational day 18(1/2), fetuses were examined for gross external malformations and prepared for skeletal analysis by using Alizarin Red S staining. RESULTS: No significant gross external malformations were observed in any of the study groups. Fetal weights were significantly reduced in most study groups. Resorption rates were significantly increased only in the 2,000-mg/kg/day LEV group. The overall incidence of skeletal abnormalities and specifically of hypoplastic phalanges was significantly increased in both PBA treatments and in the intermediate 1,200-mg/kg/day LEV group. In contrast to that in humans, 24-h urinary excretion analysis in mice showed that 65-100% of the LEV doses were excreted unchanged, whereas only 4% was excreted as the metabolite PBA. CONCLUSIONS: Results of this study demonstrate that both LEV and its major metabolite in humans, PBA, do not induce major structural malformations in developing SWV/Fnn embryos and suggest that they provide a margin of reproductive safety for the pregnant epileptic population when compared with other AEDs tested in this mouse model.  相似文献   

20.
PURPOSE: To determine the prevalence of secondary (symptomatic) epilepsy and to ascertain levels of seizure control and intellectual function in a clinic population of children drawn from a poor community in a temperate region of South Africa. METHODS: Detailed review of the records of every child with recurrent seizures who attended a special epilepsy outpatient clinic during 1995. RESULTS: A total of 1,017 children was studied. In 432 (43%), there was historic, clinical, and radiologic evidence to suggest that epilepsy was symptomatic of underlying brain damage or defect. Acceptable seizure control was maintained with a single standard anticonvulsant drug (AED) in 65% of cases. In the 6 months preceding the study, 37% of the subjects had remained seizure free. Forty-seven percent of the study population were considered to be of subnormal intelligence. CONCLUSIONS: In a children's hospital outpatient population in the Western Cape region of South Africa, the prevalence of secondary epilepsy is higher than is found in developed countries. There is need within the community for preventive measures aimed at reducing the prevalence of perinatal insults, meningitis, tuberculosis, neurocysticercosis, and cerebral trauma.  相似文献   

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