RESUMO
PLG potentiates the action of levodopa in 6-OH-DA-treated rats. PLG plus levodopa is more effective than levodopa alone. PLG-treated rats have a decreased concentration of Leu-enkephalin in the caudate nucleus as compared with the control. Preliminary results of using PLG (400 mg/day) for 10 days for treating PD are satisfactory. The mode of action of PLG with relation to dopamine-enkephalin interaction is discussed.
Assuntos
Antiparkinsonianos/uso terapêutico , Hormônio Inibidor da Liberação de MSH/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Idoso , Animais , Encéfalo/efeitos dos fármacos , Encefalina Leucina/metabolismo , Feminino , Humanos , Hidroxidopaminas/toxicidade , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Oxidopamina , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson Secundária/tratamento farmacológico , Ratos , Comportamento Estereotipado/efeitos dos fármacosRESUMO
To investigate the vasorelaxant effect of puerarin, tension was recorded from rat thoracic aortic rings. Puerarin completely relaxed the contractions induced by phenylephrine (PE) in a concentration-dependent manner in endothelium-intact and endothelium-denuded rat aorta, while had no effect on those preconstricted by a high concentration of potassium chloride (60 mM). Also, puerarin had no effects on the transient contraction elicited by PE or caffeine in Ca2+- free medium. The relaxant effect of puerarin was significantly inhibited by pretreatment of endothelium-denuded aorta with potassium channel antagonists tetraethylammonium and 4-aminopyridine, but not glibenclamide. These results indicate that puerarin induces an endothelium-independent relaxation in rat aortic rings. The mechanisms may involve the reduction in Ca2+ influx through the non-voltage-sensitive calcium channels and the activation of the potassium channels (voltage-activated K+ channels and large conductance Ca2+ -activated K+ channels, but not ATP-sensitive K+ channels).