PubMed:11226639 JSONTXT

{"project":"bc5cdr-valid-experiment","denotations":[{"id":"T1","span":{"begin":16,"end":25},"obj":"Chemical"},{"id":"T2","span":{"begin":29,"end":40},"obj":"Chemical"},{"id":"T3","span":{"begin":49,"end":57},"obj":"Disease"},{"id":"T4","span":{"begin":67,"end":76},"obj":"Chemical"},{"id":"T5","span":{"begin":175,"end":183},"obj":"Disease"},{"id":"T6","span":{"begin":185,"end":203},"obj":"Chemical"},{"id":"T7","span":{"begin":271,"end":280},"obj":"Chemical"},{"id":"T8","span":{"begin":310,"end":319},"obj":"Chemical"},{"id":"T9","span":{"begin":360,"end":371},"obj":"Chemical"},{"id":"T10","span":{"begin":372,"end":380},"obj":"Disease"},{"id":"T11","span":{"begin":507,"end":518},"obj":"Chemical"},{"id":"T12","span":{"begin":519,"end":527},"obj":"Disease"},{"id":"T13","span":{"begin":562,"end":571},"obj":"Chemical"},{"id":"T14","span":{"begin":682,"end":690},"obj":"Disease"},{"id":"T15","span":{"begin":727,"end":736},"obj":"Chemical"},{"id":"T16","span":{"begin":800,"end":808},"obj":"Chemical"},{"id":"T17","span":{"begin":813,"end":821},"obj":"Chemical"},{"id":"T18","span":{"begin":830,"end":838},"obj":"Disease"},{"id":"T19","span":{"begin":865,"end":874},"obj":"Chemical"},{"id":"T20","span":{"begin":894,"end":902},"obj":"Disease"},{"id":"T21","span":{"begin":932,"end":943},"obj":"Chemical"}],"text":"Dual effects of melatonin on barbiturate-induced narcosis in rats.\nMelatonin affects the circadian sleep/wake cycle, but it is not clear whether it may influence drug-induced narcosis. Sodium thiopenthal was administered intraperitoneally into male rats pre-treated with melatonin (0.05, 0.5, 5 and 50 mg/kg). Melatonin pre-treatment affected in a dual manner barbiturate narcosis, however, no dose-effect correlation was found. In particular, low doses reduced the latency to and prolonged the duration of barbiturate narcosis. In contrast, the highest dose of melatonin (50 mg/kg) caused a paradoxical increase in the latency and produced a sustained reduction of the duration of narcosis, and a reduction in mortality rate. Melatonin 0.5 and 5 mg/kg influenced the duration but not the latency of ketamine- or diazepam-induced narcosis. Thus, the dual action of melatonin on pharmacological narcosis seems to be specific for the barbiturate mechanism of action."}