Differential feeding responses evoked in the rat by NPY and NPY1-27 injected intracerebroventricularly.
Neuropeptide Y (NPY) given by the intracerebroventricular (ICV) route in the rat evokes hyperphagic-like feeding. To examine the molecular nature of action of NPY, comparisons were made between the central effects of this peptide and a newly synthesized amino-terminus fragment, NPY1-27. A single guide tube was implanted stereotaxically to rest just above a lateral cerebral ventricle so that ICV injections in a volume of 10 microliters of either CSF control vehicle or peptide could be given in the unrestrained rat. Native NPY or NPY1-27 was given in doses of 5.0 or 10.0 micrograms, whereas nondeprotected NPY was infused in a dose of 10.0 micrograms. The intakes of either regular commercial rat diet or specially prepared chocolate-flavored biscuits as well as water were recorded intermittently for 4.0 h following each ICV infusion. Although a clear-cut dose response with a latency of similar magnitude emerged for both molecules, NPY was found to be nearly twice as potent as NPY1-27 in inducing spontaneous feeding. A corresponding infusion in the same volume of either nondeprotected NPY or CSF control vehicle was without effect. When chocolate-flavored biscuits were provided to the rat, an ICV infusion of a 10.0 micrograms dose of NPY enhanced significantly both rate of eating and total cumulative intake of flavored food in comparison to that after a similar infusion of NPY1-27 or either control solution. These results suggest that native NPY acting centrally affects gustatory and/or olfactory systems to a much greater degree than does NPY1-27.(ABSTRACT TRUNCATED AT 250 WORDS)
Paez
X
X
Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC 27858.
Nyce
J W
JW
Myers
R D
RD
D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D002099:Cacao; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000494:pharmacology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012527:Satiation / Q000502:physiology
D009478:Neuropeptide Y; D010446:Peptide Fragments; C069513:neuropeptide Y (1-27)