Nalmefene decreases meal size, food and water intake and weight gain in Zucker rats.
Opioids are proposed to play a role in the control of food intake since administration of opioids increase food intake while administration of opioid antagonists decrease food intake. In these experiments responses to a new opioid antagonist, nalmefene, were measured in Zucker obese and lean rats. In obese male rats 1 mg/kg nalmefene decreased the size of the first meal after a 10-hr fast and decreased 14-hr food intake, indicating nalmefene is relatively long-acting. Administration of 1 mg/kg nalmefene daily for 7 days decreased average meal size and daily food intake and increased meal frequency; feeding responses on day 7 were similar to those on day 1, suggesting a lack of development of tolerance. Food and water intake and weight gain during a 3-week treatment period were decreased more in lean rats by low doses of nalmefene (up to 0.25 mg/kg) and more in obese rats by higher doses of nalmefene (0.50 mg/kg). These responses to a new opioid antagonist further support a possible role for opioids in the control of food intake.
D000818:Animals; D001066:Appetite / Q000187:drug effects*; D001067:Appetite Depressants / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects*; D004326:Drinking / Q000187:drug effects*; D002149:Energy Intake; D005260:Female; D008297:Male; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009765:Obesity / Q000503:physiopathology; D051381:Rats; D011924:Rats, Zucker; D013997:Time Factors
D001067:Appetite Depressants; D009270:Naloxone; D009271:Naltrexone; C038981:nalmefene