Hormonal and metabolic effects of paraventricular hypothalamic administration of neuropeptide Y during rest and feeding.
To investigate the role of neuropeptide Y (NPY) in the paraventricular nucleus of the hypothalamus (PVN) in the regulation of autonomic outflow, hormonal (plasma insulin and catecholamines), metabolic (blood glucose and plasma free fatty acids) and cardiovascular (heart rate and main arterial pressure) indices were measured before, during, and after bilateral infusion of NPY (1.0, 0.2, 0.04 micrograms in 1 microliter synthetic CSF) into the PVN of conscious resting rats. Administration of the highest dose (1.0 microgram/microliter) caused bradycardia and reduced circulating norepinephrine levels without effecting circulating fuels, insulin or epinephrine. In a second experiment, feeding-induced changes in hormonal and metabolic indices were assessed after NPY administration (1.0 microgram/microliter) into the PVN. During and after feeding, NPY enhanced the feeding-induced insulin response (P < 0.01) and attenuated the feeding-induced norepinephrine response (P < 0.05). The results of the present study suggest that stimulation of NPY receptors in the PVN decreases sympathetic activity and increases parasympathetic activity in resting conditions, and that these effects are potentiated during feeding.
van Dijk
G
G
Department of Animal Physiology, University of Groningen, Haren, The Netherlands.
Bottone
A E
AE
Strubbe
J H
JH
Steffens
A B
AB
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D006339:Heart Rate / Q000187:drug effects; D006728:Hormones / Q000097:blood*; D007328:Insulin / Q000097:blood; D008297:Male; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012146:Rest
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D006728:Hormones; D007328:Insulin; D009478:Neuropeptide Y; D009638:Norepinephrine; D004837:Epinephrine