Protein secretion from rat submandibular acini and granular ducts: effects of exogenous VIP and substance P during parasympathetic nerve stimulation.
The influences of exogenous vasoactive intestinal peptide (VIP) and substance P on the release of peroxidase from acini and true tissue kallikrein (rK1) from granular ducts of the rat submandibular gland were studied during continuous parasympathetic stimulation. Parasympathetic nerve impulses caused a moderate flow of saliva (mean +/- SD, 108+/-26 microl/g tissue/min) that had a low protein concentration (174+/-88 microg/ml). The outputs of peroxidase and rK1 were minimal (14.3+/-11.8 pmol DCF/g tissue/min and 6.5+/-3.4 nmol AFC/g tissue/min, respectively). When administered intravenously, VIP had no apparent effect on the overall flow rate, but caused a significant increase in the output of peroxidase; 450% at 1 microg/kg and a further 10-fold increase at 10 microg/kg. In contrast, substance P (1 microg/kg) evoked a marked increase in flow rate (68%), and peroxidase secretion increased only 3-fold. The output of rK1 was unaffected by either VIP or substance P. Our results support the hypothesis that acinar, but not granular duct, protein secretion is evoked by non-adrenergic, non-cholinergic peptides released from parasympathetic nerve terminals.
Department of Oral Biology, University of Washington, Seattle, WA 98195, USA. copains@u.washington.edu
L C
LC
Anderson
J R
JR
Garrett
X
X
Zhang
G B
GB
Proctor
D000818:Animals; D004558:Electric Stimulation; D007275:Injections, Intravenous; D007610:Kallikreins / Q000378:metabolism; D008297:Male; D010275:Parasympathetic Nervous System / Q000502:physiology*; D009195:Peroxidase / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013363:Submandibular Gland / Q000187:drug effects* / Q000378:metabolism*; D013373:Substance P / Q000494:pharmacology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D011506:Proteins; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D009195:Peroxidase; D007610:Kallikreins