RESUMO
Evidence that beta-myrcene (MYR) interferes with the metabolic activation of premutagens has been provided by in vitro studies. In order to determine whether MYR also interferes with the in vivo metabolism of xenobiotics, thereby modifying pharmacological responses to drugs, we investigated the effects of this monoterpene on pentobarbital (PT) sleeping time in rats. Two experiments were carried out. In the first, a single dose of MYR (0.25, 0.5 or 1.0 g/kg po) was given 1 h before PT (40 mg/kg ip). No effect was observed with the two lowest doses, but the highest MYR dose given 1 h before PT increased the PT-induced sleeping time (131 +/- 15 min vs 64 +/- 15 min for controls, mean +/- SD). In the second experiment, male rats were treated with MYR (1.0 g/kg po once a day) for 14 days and injected with PT (40 mg/kg ip) 24 h after the last dose of MYR. Repeated treatment with MYR markedly reduced PT sleeping time compared to the vehicle-treated control group (21 +/- 13 min vs 35 +/- 19 min for controls, mean +/- SD). These results indicate that MYR interferes with the in vivo barbiturate metabolism and support the view that MYR induces the phenobarbital-inducible cytochrome P-450 (P-450 2B subfamily) enzymes in the rat
Assuntos
Animais , Masculino , Ratos , Pentobarbital/antagonistas & inibidores , Sono/efeitos dos fármacos , Terpenos/farmacologia , Sistema Enzimático do Citocromo P-450/biossíntese , Indução Enzimática , Pentobarbital/metabolismo , Ratos Wistar , Terpenos/administração & dosagemAssuntos
Analgesia , Animais , Apetite/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Gatos , Sistema Nervoso Central/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacologia , Diurese/efeitos dos fármacos , Cães , Feminino , Cobaias , Masculino , Camundongos , Contração Muscular/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Pentobarbital/antagonistas & inibidores , Piperazinas/farmacologia , Coelhos , Ratos , Reflexo/efeitos dos fármacos , Reserpina/antagonistas & inibidores , Transmissão Sináptica/efeitos dos fármacos , Contração Uterina/efeitos dos fármacosAssuntos
Animais , Pressão Sanguínea/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacologia , Cobaias , Niquetamida/farmacologia , Pentobarbital/antagonistas & inibidores , Pentilenotetrazol/farmacologia , Piperazinas/farmacologia , Coelhos , Ratos , Respiração/efeitos dos fármacosRESUMO
The uterotropic effect of clofibrate and phenylbutazone was studied in immature female rats. A significant increase in the uterine wet weight was observed following clofibrate and phenylbutazone administration. Clofibrate but not phenylbutazone synergized with the uterotropic effect of ethinyl-oestradiol. Phenylbutazone pretreatment significantly decreased the pentobarbitone sleeping time. The uterotropic effect of clofibrate and phenylbutazone might involve displacement of 17-beta oestradiol (or ethinyl oestradiol) from plasma albumin binding sites in rats.
Assuntos
Animais , Clofibrato/farmacologia , Sinergismo Farmacológico , Estrogênios , Etinilestradiol/farmacologia , Feminino , Tamanho do Órgão/efeitos dos fármacos , Pentobarbital/antagonistas & inibidores , Fenilbutazona/farmacologia , Ratos , Sono/efeitos dos fármacos , Útero/efeitos dos fármacosRESUMO
The interaction of pentobarbitone sodium with three analeptics viz. micoren, pentylenetetrazol and methedrine was studied in mice. Micoren prolonged pentobarbitone sleeping time. pentylenetetrazol shortened the sleeping time. Methedrine also shortened the sleeping time, but clonic convulsions of mild to severe intensity were noticed 45-60 minutes after the drug injection.