Influence of levodopa, apomorphine and 3,4-dihydroxyphenylserine (DOPS) on strychnine-induced seizures in mice.
The effects of levodopa, apomorphine and 3,4-dihydroxyphenylserine (DOPS) on tonic seizures elicited by strychnine were investigated in mice. Levodopa (6.25-100 mg/kg), apomorphine (0.2-0.8 mg/kg) and FLA-63 (12.5 mg/kg) profoundly delayed the onset and reduced the incidence of strychnine seizures. In addition, these drugs decreased strychnine-induced mortality. DOPS (1-16 mg/kg) apparently shortened the onset of strychnine seizures and altered strychnine-induced mortality in a dose-dependent manner; low doses (1-2 mg/kg) enhanced while moderate doses (4-8 mg/kg) reduced the mortality rate. FLA-63 (12.5 mg/kg) potentiated the anticonvulsant effect of low doses of levodopa (6.25-12.5 mg/kg) while it had no significant influence on the anticonvulsant effect of higher doses (25-100 mg/kg) of levodopa. In addition, the onset of strychnine seizure was further delayed by FLA-63. Haloperidol (0.5 mg/kg) potentiated the convulsant effect of strychnine (1 mg/kg) as well as strychnine-induced mortality. It also antagonised the protective effect of levodopa (12.5 and 100 mg/kg) against strychnine (1 mg/kg). Phentolamine (5 mg/kg) and +/- propranolol (1 mg/kg) antagonised strychnine seizures. Strychnine-induced mortality was also reduced by these drugs. In addition, the effects of DOPS (2 mg/kg) on strychnine seizures were antagonised by phentolamine and propranolol. These results indicate that enhancement of dopaminergic and noradrenergic neurotransmission respectively attenuate and potentiate strychnine seizures in mice.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D015103:Droxidopa / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology*; D051379:Mice; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012640:Seizures / Q000139:chemically induced*; D012694:Serine / Q000031:analogs & derivatives*; D013331:Strychnine / Q000633:toxicity*
D012694:Serine; D007980:Levodopa; D011433:Propranolol; D013331:Strychnine; D015103:Droxidopa; D001058:Apomorphine; D010646:Phentolamine