Angular bundle kindling is accelerated in rats with a genetic predisposition to acoustic stimulus-induced seizures

Limbic kindling was examined in genetically epilepsy-prone (GEPR) and non-epileptic control rats. The early stage of kindling development was accelerated in both groups of GEPR rats compared to controls. Later stages of kindling were accelerated in GEPR-9 but not GEPR-3 rats. These results indicate that GEPR rats have an enhanced susceptibility to limbic kindling and suggest that limbic brain alterations may contribute to acceleration of the early stage kindling development in GEPR rats.     

Comparison of anticonvulsant effects of valproic acid entrapped in positively and negatively charged liposomes in amygdaloid-kindled rats

Intraperitoneal injection of free valproic acid (VPA) suppressed amygdaloid-kindled seizure 1 h after injection in rats, but had no effect at 24 h. VPA entrapped in positively charged liposomes showed a prolonged anticonvulsant effect lasting for 2 days, while the effect evaluated at 1 h was not different from that with free VPA. VPA entrapped in negatively charged liposomes exerted a significantly stronger effect at 1 h than did free VPA, while it had no significant effect at 24 h. These results suggest that surface charges on liposomes play an important role in modifying the anticonvulsant effect of VPA.     

Inhibition or enhancement of kindling evolution by antiepileptics

Summary The influence of antiepileptics on the evolution of rat amygdaloid kindling was studied.Under placebo conditions clonic convulsions and a spike-wave EEG pattern developed. Diazepam, clonazepam, clobazam and phenobarbital were most effective in suppressing the evolution of kindling; the effects of valproate sodium, ethosuximide and acetazolamide were somewhat less pronounced in this respect. Carbamazepine, oxcarbazepine and phenytoin, on the other hand, enhanced kindling development, i.e. the increase in duration of after-discharge was faster than in the placebo group. The results indicate that under the above experimental conditions drugs with no anti-absence component can be distinguished from those with an anti-absence component. The mechanism of action underlying the observed effects is not yet known; the hypothesis that under special conditions protective inhibitory neuronal activity can develop to absence type seizures is proposed.     

Effect of neurotropin on seizure activity in picrotoxin kindling

Department of Normal Physiology, N. I. Pirogov Odessa Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR G. N. Kryzhanovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 3, pp. 236–239, March, 1992.     

Differential effects of kindling and kindled seizures on place learning in the morris water maze

There is some controversy about the role of long-term potentiation (LTP) in spatial learning. The authors have found that triggering generalized kindled seizures with stimulation of the perforant path disrupts spatial learning in the Morris water maze but that kindling per se does not affect spatial learning. It is suggested that abnormal electrical activity induced by high-frequency stimulation of the perforant path may have been responsible for the disruption of spatial learning previously attributed to LTP saturation.     

癫痫大鼠海马结构谷氨酸和nNOS神经元的动态变化

的：探讨谷氨酸(Glu)和一氧化氮(NO)二者在癫痫模型中的作用及其相关性。方法：戊四唑化学点燃癫痫大鼠，分为Ⅰ、Ⅲ、Ⅴ级组和Ⅴ级后24h组。采用免疫组织化学方法和图像分析技术。结果：(1)Ⅲ、Ⅴ级组Glu免疫反应阳性神经元数目和平均光密度值升高；但Ⅴ级比Ⅲ级组有所下降；Ⅴ级后24h组恢复到对照组水平。(2)Ⅴ级组和Ⅴ级后24h组nNOS免疫反应阳性神经元数目和平均光密度值升高。结论：戊四唑点燃癫痫模型中，随着点燃级别的进展，Glu的含量是呈先增加后减少的趋势，而NO的含量是逐渐增加的，提示二者在癫痫发作中既有相关性又有独立性。     

Effect of Kindling on GABAergic Neurons of the Hippocampus and Pyriform Cortex

GABAergic neurons in different fields of the hippocampus and pyriform cortex were examined 2 weeks and 1 month after electric stimulation of the ventral hippocampus. The counts of GABAergic neurons in the studied structures decreased significantly. The most pronounced shifts in the pyriform cortex were found in the central compartment. Decreased number of inhibitory elements in the two major epileptogenic structures attests to appreciable restructuring in the functions of their neuronal circles. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 7, pp. 57–59, July, 2005     

Pentylenetetrazole Kindling Induces Activation of Caspase-3 in the Rat Brain

Neuroscience and Behavioral Physiology -     

Brain somatostatin: a candidate inhibitory role in seizures and epileptogenesis

Recent evidence shows that neuropeptide expression in the CNS is markedly affected by seizure activity, particularly in the limbic system. Changes in neuropeptides in specific neuronal populations depend on the type and intensity of seizures and on their chronic sequelae (i.e. neurodegeneration and spontaneous convulsions). This paper reviews the effects of seizures on somatostatin-containing neurons, somatostatin mRNA and immunoreactivity, the release of this peptide and its receptor subtypes in the CNS. Differences between kindling and status epilepticus in rats are emphasized and discussed in the light of an inhibitory role of somatostatin on hippocampal excitability. Pharmacological studies show that somatostatin affects electrophysiological properties of neurons, modulates classical neurotransmission and has anticonvulsant properties in experimental models of seizures. This peptidergic system may be an interesting target for pharmacological attempts to control pathological hyperactivity in neurons, thus providing new directions for the development of novel anticonvulsant treatments.