Effects of intraventricular administration of neuropeptide Y on feeding behavior in fasted female rats with ventromedial hypothalamic lesions.
The role of ventromedial hypothalamic nucleus (VMN) in feeding behavior induced by central administration of porcine neuropeptide Y (NPY) in fasted female rats was investigated focusing on the effect of the intracerebroventricular (i.c.v.) injection of NPY on food intake in rats with VMN lesions after 24 h of food deprivation. Cumulative food intake was measured 1, 3 and 6 h after injection. In Exp. 1, the i.c.v. injection of NPY into intact rats stimulated food intake compared with the injection of saline 1 and 3 h after the injections in a dose dependent manner (1 h; NPY 1 microgram, 3.29 +/- 0.43, 2 micrograms, 4.64 +/- 0.88, 5 micrograms, 5.15 +/- 0.61 vs. saline 2.48 +/- 0.42 g, P < 0.05 in 2 and 5 micrograms). 5 micrograms of NPY significantly stimulated food intake 6 h later. In Exp. 2, i.c.v. injection of NPY (2 micrograms) in VMN-lesioned rats showed no significant effect on food intake compared with the injection of saline 3 weeks after VMN lesioning (1 h; NPY 2 micrograms, 2.46 +/- 0.58 vs. saline 2.39 +/- 0.12 g). These results suggest that central administration of NPY enhances food intake in fasted female rats and that the VMN is one of the crucial sites of NPY induced feeding.
Tanaka
Y
Y
Third Department of Internal Medicine, Yokohama City University, Japan.
Egawa
M
M
Inoue
S
S
Takamura
Y
Y
D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D005215:Fasting; D005260:Female; D007276:Injections, Intraventricular; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects* / Q000293:injuries / Q000473:pathology
D009478:Neuropeptide Y