PACAP 1-38 as neurotransmitter in the porcine antrum.
The concentration of PACAP 1-38 in porcine antrum amounted to 15.4+/-7.9 and 20.3+/-8 pmol/g tissue in the mucosal and muscular layers. PACAP immunoreactive (IR) fibres innervated the muscular (co-localised with VIP) and submucosal/mucosal layers (some co-storing VIP and CGRP) including myenteric and submucosal plexus and blood vessels. Only myenteric nerve cell bodies contained PACAP-IR (co-storing VIP). In isolated perfused antrum, vagus nerve stimulation (8 Hz) and capsaicin (10(-5) M) increased PACAP 1-38 release. PACAP 1-38 (10(-9) M) increased substance P (SP), gastrin releasing peptide (GRP) and VIP release. PACAP 1-38 (10(-8) M) inhibited gastrin secretion and stimulated somatostatin secretion and motility dose-dependently. PACAP-induced motility was strongly inhibited by the antagonist PACAP 6-38 but also by atropine and substance P-antagonists (CP99994/SR48968) but PACAP 6-38 had no effect on vagus-induced secretion or motility.


CONCLUSIONS
PACAP 1-38 may be involved in antral motility and secretion by interacting with cholinergic, SP-ergic, GRP-ergic and/or VIP-ergic neurones, and may also be involved in afferent reflex pathways.
Tornøe
K
K
Department of Medical Physiology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, Dk-2200, N, Copenhagen, Denmark.
Hannibal
J
J
Georg
B
B
Schmidt
P T
PT
Hilsted
L
L
Fahrenkrug
J
J
Holst
J J
JJ
D000818:Animals; D046508:Culture Techniques; D004558:Electric Stimulation; D019886:Gastrin-Releasing Peptide / Q000378:metabolism; D005755:Gastrins / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000187:drug effects; D007150:Immunohistochemistry; D009197:Myenteric Plexus / Q000378:metabolism; D009479:Neuropeptides / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000494:pharmacology*; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011706:Pyloric Antrum / Q000294:innervation* / Q000378:metabolism / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D013004:Somatostatin / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D013552:Swine; D014630:Vagus Nerve / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D005755:Gastrins; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D010446:Peptide Fragments; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; C108046:pituitary adenylate cyclase-activating-peptide (1-38), pig; C075647:pituitary adenylate-cyclase-activating-peptide (6-38); D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D019886:Gastrin-Releasing Peptide