RESUMEN
Effect of pretreatment of intraperitoneally administered Ca-channel blockers Nifedipine (5, 10, 20 mg/kg). Verapamil (5, 10, 20 mg/kg) and Diltiazem (5, 10, 20 mg/kg) was studied on Haloperidol-induced catalepsy and Methamphetamine-induced stereotypy in albino rats. All these drugs reduced the onset of catalepsy, significantly increased the cataleptic score and delayed the onset and inhibited the Methamphetamine-induced stereotypy. The possible involvement of dopaminergic and adrenergic mechanisms and modification by Ca-channel blockers are discussed.
Asunto(s)
Animales , Bloqueadores de los Canales de Calcio/farmacología , Catalepsia/inducido químicamente , Depresores del Sistema Nervioso Central/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Diltiazem/farmacología , Femenino , Haloperidol/farmacología , Masculino , Metanfetamina/farmacología , Nifedipino/farmacología , Ratas , Ratas Wistar , Conducta Estereotipada/efectos de los fármacos , Verapamilo/farmacologíaRESUMEN
In doses (from 100 mug to 1 mg) nicotinic acid produced positive inotropic and chronotropic action on isolated frog heart. This effect was blocked by pronethalol and guanethidine administration. This effect was not observed in reserpinised frogs. Repeated administration of the same dose of nicotinic acid caused development of tachyphylaxis, in frog's heart preparation. The observations indicate that nicotinic acid induced a release of noradrenaline in frog's heart. On other preparations, such as isolated rabbit heart, rabbit's intestine and guinea pig seminal vesicles, nicotinic acid produced a nonspecific direct depressant action.