Hypothermic effect of neuromedin N in mice and its potentiation by peptidase inhibitors

Abstract The intracerebroventiculaar administration of neuromedin N (from 50 ng to 5 μg) elicited a dose- and time-dependent hypothermia in mice. Two aminopeptidase inhibitors, bestatin (50 μg) and puromycin (50 μg), the endopeptidase 24.11 inhibitor, thiorphan (10 μg), and the angiotensin-converting enzyme inhibitor, captopril (50 μg), were tested for their ability to potentiate the neuromedin N-induced hypothermia. Only bestatin significantly increased the response to the peptide. In addition, thiorphan, though devoid of effect on the neuromedin N-induced hypothermia when given alone, further potentiated the response elicited by neuromedin N and bestatin. The combinations of puromycin/ thiorphan and bestatin/captopril did not potentiate the neuromedin N-induced hypothermia.