Facilitation of kindled seizures in rats fed choline-supplemented diets

Diet composition modifies the toxicity of repeated soman exposure in rats

It was previously demonstrated that diet potently modulates the toxic effects of an acute lethal dose of the nerve agent soman. The current investigation was undertaken to examine the influence of diet on the cumulative toxicity of repeated soman administration. Rats were fed one of four distinct diets (standard, choline-enriched, glucose-enriched, or ketogenic) for four weeks prior to and throughout a repeated soman dosing and recovery regimen. Each diet group included animals exposed to an equivalent volume of saline that served as negative controls. In exposure Week 1, animals received three consecutive daily doses of 0.4 LD(50) soman. In exposure Week 2, animals received four consecutive daily doses of 0.5 LD(50) soman. In exposure Week 3, animals received five consecutive daily doses of 0.5 LD(50) soman. Week 4 constituted a post-exposure recovery evaluation. Throughout the experiment, behavioral function was assessed by a discriminated avoidance test that required intact sensory and motor function. Survival and body weight changes were recorded daily. Differences in toxicity as a function of diet composition became apparent during the first week. Specifically, rats fed the glucose-enriched diet showed pronounced intoxication during Week 1, resulting in imperfect survival, weight loss, and deteriorated avoidance performance relative to all other groups. All rats fed the glucose-enriched diet died by the end of exposure Week 2. In contrast, only 10% of animals fed the standard diet died by the end of Week 2. Also in Week 2, weight loss and disrupted avoidance performance were apparent for all groups except for those fed the ketogenic diet. This differential effect of diet composition became even more striking in Week 3 when survival in the standard and choline diet groups approximated 50%, whereas survival equaled 90% in the ketogenic diet group. Avoidance performance and weight loss measures corroborated the differential toxicity observed across diet groups. Upon cessation of soman exposure during the final week, recovery of weight and avoidance performance in survivors was comparable across diet groups. These results systematically replicate previous findings demonstrating that diet composition exacerbates or attenuates toxicity in rodents exposed acutely to organophosphorus compounds.

Herbal remedies, dietary supplements, and seizures

The use of herbal remedies and dietary supplements is widespread throughout the world, and use may be increasing. These are taken for a wide range of perceived benefits, such as energy and memory enhancement and treatment of specific conditions. Individuals with and without epilepsy may use these substances and may not inform their treating physician unless specifically asked. Inquiry about herbal medicine and dietary supplement intake should now be part of routine clinical history taking. Anecdotal accounts suggest that some herbal substances may have anticonvulsant effect, but randomised double-blind controlled trails are lacking. Alternatively many herbals and dietary supplements may predispose to seizures in individuals without epilepsy and worsen seizure control in those with epilepsy. In this article, we review the potential anticonvulsant and proconvulsant effects of herbal remedies and dietary supplements and discuss the potential interaction between these herbal substances and conventional anticonvulsant medications.

Ibotenic acid lesions of the basal forebrain cholinergic system retard amygdala kindling

The effect of ibotenate lesions of septum and substantia innominata on electrical kindling of the amygdala was investigated in rats. The lesions significantly retarded kindling in the absence of a change in initial seizure sensitivity. This suggests that cholinergic neurotransmission can contribute to, but is not crucial for, amygdala kindling, and that a major component of the cholinergic circuitry involved in amygdala kindling may originate in the septum or substantia innominata or both.

Failure of aspartame to affect seizure susceptibility in kindled rats

The effect of aspartame administered by gavage to rats on amygdala and hippocampal kindled seizures was assessed. Despite the administration of a wide range of doses (25-2000 mg/kg) no evidence for an effect of aspartame on afterdischarge threshold or seizure strength was obtained when testing was done at a time when serum and brain levels of neutral amino acids are known to be significantly elevated as a result of this treatment. There is controversy whether dietary aspartame (N-L-aspartyl-L-phenylalanine 1-methyl ester), a food additive sweetner, can lead to seizures in susceptible humans and in laboratory animals. A proseizure effect of high consumption of aspartame has been alleged (Wurtman, 1985; Walton, 1986) and denied (Gaull, 1985). Recent studies using mice have yielded mixed results. Thus, Kim and Kim (1986) and Pinto and Maher (1988) observed potentiating effects of high loads of aspartame on chemically induced seizures, but Nevins, Arnolde and Haigler (1986) observed no effect on chemical and ECS seizures. We used the electrical kindling model of epilepsy to assess whether aspartame can alter seizure threshold or strength in rats. The kindled response is highly repeatable and stable and has been shown to be sensitive to a large variety of pharmacological treatments (Racine, 1978) and to dietary manipulation (McCann, Cain and Philbrick, 1983).