Hypothalamic neuropeptide Y inhibits gastric acid output in rat: role of the autonomic nervous system.
Injection of neuropeptide Y (NPY) into the hypothalamic paraventricular nucleus (PVN) inhibits gastric acid secretion in anesthetized rats. The role of the autonomic nervous system in mediation of this response was investigated. Unilateral microinjection of 200 pmol NPY into the PVN of anesthetized rats inhibited spontaneous and pentagastrin-stimulated gastric acid output. Inhibition was abolished by subdiaphragmatic vagotomy, atropine, and bethanechol but was restored by electrical stimulation of the distal cut end of the vagus in cervically vagotomized rats. Although sympathectomy, phenoxybenzamine, and yohimbine abolished the inhibition, it was not affected by prazosin treatment. Gastric blood flow was not altered by injection of NPY. These results suggest that the antisecretory effect of NPY in the PVN was sympathetically mediated via suppression of gastric vagal cholinergic tone through activation of alpha 2-adrenoceptors.
Department of Medical Physiology, Faculty of Medicine, University of Calgary, Alberta, Canada.
G A
GA
Humphreys
J S
JS
Davison
W L
WL
Veale
D000818:Animals; D001286:Atropine Derivatives / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000502:physiology*; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology; D004558:Electric Stimulation; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D008845:Microinjections; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D010418:Pentagastrin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014628:Vagotomy / Q000379:methods
D001286:Atropine Derivatives; D001626:Bethanechol Compounds; D009478:Neuropeptide Y; D018723:Bethanechol; C006649:methylatropine; D010418:Pentagastrin