Abstract-The present study was undertaken to examine how morphine changes food and water intake in non-fasted or fasted rats with different administration times. Morphine (1, 3 and 10 mg/kg) was intraperitoneally administered at 10:45 (light period) or 18:45 (dark period). Morphine increased food and water intake in non-fasted rats 2 hr after the administration during the light period, whereas the total daily intakes were decreased. In contrast, morphine decreased food and water intake in non-fasted rats during the dark period and in fasted rats during both the light and dark period. These results suggest that morphine disorders the baseline levels of feeding and water drinking of naive rats.
Abstract-The present study was undertaken to investigate the relationships between morphine-induced feeding and the adrenal functions. Morphine (5 mg/kg) was intraperitoneally administered at 10:45 (light period) or 18:45 (dark period). The orectic effects of morphine during the light period in normal rats were not influenced by adrenalectomy; however, the anorectic effects during the dark period in normal rats were attenuated by both adrenalectomy and adrenodemedullation. Corticos terone (10 mg/kg) itself had no effects on feeding during the light and dark period. Morphine did not alter blood insulin levels during the light period, but markedly decreased it during the dark period independently of feeding. These results show that morphine has two different effects on feeding by administration time, and they suggest that the adrenal affects morphine-induced feeding only during the dark period (hungry state), presumably through insulin release, but not during the light period (satiated state).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.