RESUMO
The phenomenon of tolerance to the analgesic action of tremorine in mice was studied by the hot-plate and tail-clip methods. Reduction in 5-HT levels in brain by parachlorophenylalamine pretreatment decreased the ED50 of tremorine analgesia in tremorine tolerant mice. 5-Hydroxyptophan, L-Dopa or alpha-methyl-para-tyrosine did not influence the analgesic response to tremorine in tremorine tolerant animals. However, theophylline was found to enhance the tolerance to tremorine analgesia. Brain 5-HT and cAMP are probably involved in tremorine tolerance, whereas neither noradrenaline nor dopamine is involved in the phenomenon.
Assuntos
Analgésicos , AMP Cíclico/fisiologia , Serotonina/fisiologia , Tremorina/farmacologia , 5-Hidroxitriptofano/farmacologia , Animais , Interações Medicamentosas , Tolerância a Medicamentos , Fenclonina/farmacologia , Levodopa/farmacologia , Masculino , Metiltirosinas/farmacologia , Camundongos , Teofilina/farmacologia , Fatores de TempoRESUMO
Muscimol, a structural analog of GABA, significantly potentiated pilocarpine-induced analgesia in rats, but failed to alter pilocarpine-induced catalepsy. It also failed to affect pilocarpine-elicited increase in homovanillic acid levels in the striatum. These findings suggest that the potentiation of pilocarpine-induced analgesia by muscimol is unrelated to an interaction of the GABAergic system with the striatal cholinergic or dopaminergic systems.