Subsensitivity to muscimol-induced catalepsy after long-term administration of phenytoin in rats

✍ Scribed by Robert Lalonde; M. I. Botez

• Book ID: 104771354
• Publisher: Springer
• Year: 1985
• Tongue: English
• Weight: 440 KB
• Volume: 86
• Category: Article
• ISSN: 0033-3158
• DOI: 10.1007/bf00431687

✦ Synopsis

Male albino rats were injected with 25 mg/kg of phenytoin (PHT) every day for 20 consecutive days and were tested on days 21 and 28 for their response to 1 or 2 mg/kg of muscimol, a GABA receptor agonist. Rats treated with PHT showed a decreased responsiveness to muscimol-induced catalepsy (2 mg/kg) on day 21 but not on day 28. Acutely administered PHT, on the contrary, had a tendency to potentiate muscimol-induced catalepsy. Muscimol-induced catalepsy was not antagonized by acute treatment with bicuculline (0.5 2.0 mg/kg). It is proposed that withdrawal after long-term administration of PHT reduces the sensitivity of a GABA receptor site not sensitive to bicuculline.