Differential inhibition of galanin- and ghrelin-induced food intake by i.c.v. GLP-1(7-36)-amide.
Feeding regulation involves both anorectic and orexigenic neuropeptides mainly located in the hypothalamus. To gain further insight into the interaction between these two groups of regulators inhibition of feeding induced by glucagon-like peptide-1 (GLP-1) was examined during stimulation of food intake by equimolar doses of ghrelin and galanin. The experiments were carried out in freely feeding rats. Intracerebroventricular (i.c.v.) injections were accomplished through stereotaxically implanted cannulae aimed at the lateral cerebral ventricle. Food intake of standard rat chow pellets was subsequently recorded for 2 h. Ghrelin and galanin stimulated food intake significantly with no difference between these two peptides. During ghrelin stimulation GLP-1 inhibited feeding in doses between 0.015 and 1.5 nmol. During galanin stimulation of food intake a ten fold higher dose (0.15 nmol) was required to inhibit food intake. In conclusion equimolar doses of i.c.v. ghrelin and galanin are similarly effective stimuli of food intake when given alone. However in combination with an anorectic neuropeptide such as GLP-1 they have substantially different potencies of feeding stimulation. Such interaction could also be of interest for therapeutic strategies involving both regulating groups of neuropeptides.
Schusdziarra
Volker
V
Else-Kröner-Fresenius Center of Nutritional Medicine, Technical University of Munich, Germany. volker.schusdziarra@lrz.tum.de
Zimmermann
Jens-Peter
JP
Erdmann
Johannes
J
Bader
Ulrich
U
Schick
Rafael R
RR
D000818:Animals; D004435:Eating / Q000187:drug effects*; D019004:Galanin / Q000008:administration & dosage / Q000037:antagonists & inhibitors*; D054439:Ghrelin / Q000008:administration & dosage / Q000037:antagonists & inhibitors*; D052216:Glucagon-Like Peptide 1 / Q000008:administration & dosage / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D054439:Ghrelin; D010446:Peptide Fragments; C055453:glucagon-like peptide 1 (7-36)amide; D019004:Galanin; D052216:Glucagon-Like Peptide 1