Susceptibility to audiogenic seizure induced by thiosemicarbazide

Abstract

Rats, cats, and monkeys were subjected to audiogenic stimuli after the administration of thiosemicarbazide (TSC). The treated rats responded to audiogenic stimulation with episodic running behavior (ERB) with or without convulsion (C), the most effective dosage being 4.4 mg/kg. In rats, the pattern of audiogenic response in genetically sensitive rats and TSC-treated nonsensitive rats was indistinguishable. Treatment of audiogenic-sensitive rats with TSC produced some accentuation of audiogenic response. Cats responded to audiogenic stimulation with ERB, ERB + C, C + ERB, or C alone. In addition, entirely independent and spontaneous convulsion was observed. The threshold dosage was 7.0 mg/kg. Monkeys responded to audiogenic stimulation with C, motor excitement followed by C, or C followed by repetitive vocalization or motor excitement. Monkeys also showed independent and spontaneous C. In cats and monkeys, unlike methionine sulfoximine-induced episodic behavior, spontaneous C and audiogenic response were not mutually exclusive. Although some electrographic evidence of preferential involvement of temporal lobe structures was obtained, no discernible seizure discharge was observed in any brain structures explored during ERB or restlessness induced by audiogenic stimulation. In spite of some interspecies response variation it was conclusively shown that TSC induces transient audiogenic seizure susceptibility in rats, cats, and monkeys.