Vasoactive intestinal peptide. An inhibitor of feline gastric smooth muscle in vitro.
Dose-response characteristics of feline corpus circular muscle were studied in vitro for three neuropeptides individually and with vasoactive intestinal peptide. Bombesin, substance P, and cholecystokinin-octapeptide each elicited concentration-dependent isometric contractions that were reduced by 10(-8) M or 10(-7) M vasoactive intestinal peptide (P less than 0.01). The concentration of each neuropeptide producing a half-maximal response was increased more than one logfold to greater than or equal to 10(-6) M by vasoactive intestinal peptide. Tetrodotoxin blocked responses to bombesin (P less than 0.001) and reduced responses to substance P (P less than 0.05), but had no effect on responses to cholecystokinin-octapeptide (P greater than 0.1). These results demonstrate inhibition of neuropeptide responses of gastric smooth muscle and support vasoactive intestinal peptide as an inhibitory regulator of gastric motor function.
Merlo
A
A
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
Cohen
S
S
D000818:Animals; D001839:Bombesin / Q000037:antagonists & inhibitors; D002415:Cats; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D012844:Sincalide / Q000037:antagonists & inhibitors; D013270:Stomach / Q000187:drug effects*; D013373:Substance P / Q000037:antagonists & inhibitors; D013779:Tetrodotoxin / Q000037:antagonists & inhibitors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013779:Tetrodotoxin; D012844:Sincalide; D001839:Bombesin