Effect of Brewer's yeast-induced pyrexia on aminophylline-elicited convulsions in mice.

Theophylline-associated convulsions have been observed most frequently in children with fever, but the mechanism is not fully understood. In this study, we investigated the basic mechanism of aminophylline [theophylline-2-ethylenediamine]-induced convulsions and the effects of Brewer's yeast-induced pyrexia in mice. Diazepam (5-10mg/kg, i.p.), a benzodiazepine receptor agonist, significantly prolonged the onset and significantly decreased the incidence of convulsions induced by aminophylline (350 mg/kg, i.p.). However, the gamma aminobutyric acid (GABA)A receptor agonist muscimol (1-4 mg/kg, i.p.), the GABAB receptor agonist baclofen (2-4 mg/kg, i.p.) and the N-methyl-D-aspartic acid receptor antagonist dizocilpine (0.1-0.3 mg/kg, i.p.) failed to protect against the convulsions. 20% Brewer's yeast (0.02 ml/g, s.c.) increased body temperature by 1.03, and also significantly shortened the onset and significantly increased the incidence of convulsions induced by aminophylline. The anticonvulsant action of diazepam (2.5-10mg/kg, i.p.) on the convulsions induced by aminophylline was reduced by Brewer's yeast-induced pyrexia. The proconvulsant actions of the GABAA receptor antagonists picrotoxin (3-4 mg/kg, i.p.) and pentylenetetrazol (40-60 mg/kg, i.p.) were enhanced by Brewer's yeast. These results suggest that the anticonvulsant action of diazepam against aminophylline is reduced by Brewer's yeast-induced pyrexia, and that GABAA receptors are involved in the aggravation of the convulsions by Brewer's yeast in mice.