title: Regulation of secretion by vasoactive intestinal peptide in isolated perfused rat submandibular glands.
abstract: The isolated, perfused gland was used to examine the regulation of saliva volume and protein content by vasoactive intestinal peptide (VIP). In the absence of other secretagogues, VIP produced a modest, sustained saliva flow with a biphasic dose-response curve in which saliva volume was greatest at 1 nM VIP (28.5 +/- 3.8 microliters in the first 5 min, n = 4) but reduced at lower and higher concentrations. The protein concentration in saliva released in response to VIP (0.86 +/- 0.13 micrograms/microliters) was substantially higher than with 30 nM acetylcholine (0.06 +/- 0.02 micrograms/microliters) or 1 nM substance P (0.30 +/- 0.05 micrograms/microliters). During the first 5 min of stimulation, VIP and substance P were synergistic in terms of volume and protein content whereas inclusion of VIP did not increase acetylcholine-stimulated flow in the first 5 min but produced a higher sustained flow over the next hour. After stimulation with acetylcholine, subsequent addition of VIP transiently enhanced saliva volume and protein content in a monophasic, dose-dependent manner with effects at 1 pM VIP and higher. The responses were different for VIP compared with other cAMP-mobilizing agents and the involvement of multiple VIP receptor subtypes was suggested from experiments in which a VIP antagonist blocked the VIP enhancement of saliva volume but not the increase in protein.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Missouri-Columbia 65212.
authors.forename: J T
authors.initials: JT
authors.lastname: Turner
authors.forename: J M
authors.initials: JM
authors.lastname: Camden
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage / Q000494:pharmacology*; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D010478:Chemotherapy, Cancer, Regional Perfusion; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012463:Saliva / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000032:analysis*; D012636:Secretory Rate / Q000187:drug effects; D013363:Submandibular Gland / Q000187:drug effects* / Q000378:metabolism; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology*; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D010446:Peptide Fragments; D012471:Salivary Proteins and Peptides; D005576:Colforsin; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; C047945:vasoactive intestinal peptide (10-28); D000242:Cyclic AMP; D000527:Alprostadil; D007545:Isoproterenol; D000109:Acetylcholine