EVIDENCE OF GABAERGIC MODULATION IN MELATONIN-INDUCED SHORT-TERM-MEMORY DEFICITS AND FOOD-CONSUMPTION

Many of the the pharmacological effects of melatonin have been found t o be similar to those of benzodiazepines. In the present study we anal yzed the role of melatonin on short-term memory retrieval on transfer latency in elevated plus maze and food consumption behavior; and the e ffects were compared with those of diazepam. Melatonin dose-dependentl y (10-100 mg/kg) produced short-term memory deficit and it potentiated diazepam-(I mg/kg) induced cognitive deficit in mice. Flumazenil (1 a nd 4 mg/kg) could reverse enhancement in diazepam-induced memory defic it by melatonin. Chronic treatment with melatonin (10 mg/kg/7d) produc ed a similar profile in transfer latency on elevated pills mate compar ed with that of diazepam. In a food consumption behavior study melaton in (25 and 50 mg/kg) produced a significant hyperphagic effect compare d to control. Flumazenil (4 mg/kg) could significantly reverse the hyp erphagic effects induced by diazepam (2 mg/kg), but would be insignifi cant with regard to that due to melatonin. These findings provide furt her evidence that some of the pharmacological effects of melatonin mel atonin are comparable with those of diazepam and may involve central G ABAergic mechanism, (C) 1998 Prous Science. All rights reserved.