Central injection in rats of alpha-melanocyte-stimulating hormone analog: effects on food intake and brain Fos.
Lateral cerebroventricular (LCVT) administration of the alpha-MSH agonist analog Nle4DPhe7alpha-MSH (NDP-MSH) inhibited food intake in food-deprived rats, but did not inhibit water intake in water-deprived rats. When NDP-MSH was administered into the fourth ventricle (4CVT), comparable suppressions of food intake were observed. LCVT and 4CVT administration of NDP-MSH also reduced spontaneous 24 h food intake. LCVT injection of NDP-MSH greatly attenuated food intake stimulated in sated rats by acute CVT administration of neuropeptide Y (NPY). These and other data suggest that alpha-MSH is an important endogenous regulator of food intake, possibly acting downstream of NPY. In an attempt to assess further the sites of action of NDP-MSH, a qualitative mapping study of Fos-like immunoreactive (Fos-ir) neurons was performed following LCVT administration of NDP-MSH. LCVT injection of NDP-MSH induced Fos-ir in several forebrain regions including cortex, striatum, bed nucleus of the stria terminalis, paraventricular nucleus of the hypothalamus and arcuate nucleus. The combination of NPY and NDP-MSH did not produce obvious antagonism or cancellation of effects in any region examined. Thus, the site(s) of action of NDP-MSH on food intake remain to be clarified.
Brown
K S
KS
Department of Psychology, University of Florida, Gainesville 32611-2250, USA.
Gentry
R M
RM
Rowland
N E
NE
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002552:Cerebral Ventricles / Q000378:metabolism*; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D005260:Female; D007150:Immunohistochemistry; D007267:Injections; D008297:Male; D009478:Neuropeptide Y / Q000494:pharmacology; D016761:Oncogene Proteins v-fos / Q000276:immunology / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000521:alpha-MSH / Q000031:analogs & derivatives* / Q000494:pharmacology
D009478:Neuropeptide Y; D016761:Oncogene Proteins v-fos; D010446:Peptide Fragments; D000521:alpha-MSH; C027756:MSH, 4-Nle-7-Phe-alpha-