Pertussis toxin inhibits neuropeptide Y-induced feeding in rats.
Neuropeptide Y (NPY) is the most powerful peptide drug stimulating feeding in rats. Rats with paraventricular hypothalamic (PVH) cannulae were used to investigate the mechanisms involved in NPY-induced feeding. Consistent with previous reports, injection of 2 micrograms of NPY into the PVH significantly increased the cumulative food intake over 1-, 2- and 4-hr periods. Ad lib feeding decreased significantly two days after pertussis toxin (PT) administration, but recovered to nearly normal levels on the fourth day. PT had no immediate effect on NPY-induced feeding; however, four days after PT was injected NPY (2 micrograms) did not increase the food intake compared to control. In vitro investigations showed that isoproterenol-stimulated adenylate cyclase activity in the hypothalamus of control rats was inhibited by NPY. In PT-treated rats, however, no inhibition of cAMP production was observed. These results suggest that cAMP may mediate NPY-induced feeding and that a PT-sensitive G protein may be involved in this signal transduction.
Chance
W T
WT
Department of Surgery, University of Cincinnati Medical Center, OH 45267.
Sheriff
S
S
Foley-Nelson
T
T
Fischer
J E
JE
Balasubramaniam
A
A
D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D000242:Cyclic AMP / Q000096:biosynthesis; D005247:Feeding Behavior / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects / Q000201:enzymology; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors*; D037342:Pertussis Toxin; D051381:Rats; D011919:Rats, Inbred Strains; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D037361:Adenylate Cyclase Toxin; D009478:Neuropeptide Y; D010566:Virulence Factors, Bordetella; D000242:Cyclic AMP; D037342:Pertussis Toxin; D000262:Adenylyl Cyclases; D007545:Isoproterenol