Endomorphins have orexigenic and anxiolytic activities in mice.
This study was designed to investigate the effects of endomorphin 1 and 2, recently identified mu-opioid receptor selective peptides, on food intake and anxiety in non-food-deprived mice. The intracerebroventricular (i.c.v.) injection of either endomorphin 1 or 2 (0.03-30 nmol) increased food intake in a dose-related manner. A significant increase was observed 20 min after i.c.v. injection of endomorphin 1 or 2 and continued for 4 h. In the elevated plus maze test, the i.c.v. injection of endomorphin 1 (30 nmol) significantly decreased the normal preference for the closed arms. These results suggest that endomorphin produces orexigenic and anxiolytic effects, and that the mu-opioid receptor contributes to the regulation of feeding and anxiety in mice.
Asakawa
A
A
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Inui
A
A
Momose
K
K
Ueno
N
N
Fujino
M A
MA
Kasuga
M
M
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D019167:Appetite Stimulants / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D017450:Receptors, Opioid, mu / Q000819:agonists; D013268:Stimulation, Chemical
D014151:Anti-Anxiety Agents; D019167:Appetite Stimulants; D009842:Oligopeptides; D017450:Receptors, Opioid, mu; C105293:endomorphin 1; C105294:endomorphin 2