Effects of regulatory peptides on the porcine lower oesophageal sphincter.
Studies were performed to investigate the effects of neurotransmitters and neurotransmitter candidates (substance P, VIP, somatostatin, Met-enkephalin, gastrin-17, CCK-4 and -8, neurotensin and TRH) of the newly discovered peptidergic nervous system on lower oesophageal sphincter pressure in anaesthetized pigs. All neuropeptides were infused over 2 min periods in 6 different doses, separated by resting periods of at least 1 min, directly into the arterial supply of the lower oesophageal sphincter. Substance P caused a dose-dependent increase in lower oesophageal shpincter pressure; the threshold dose was 9 pmol . kg-1 . min-1 and half maximal response occurred at 72 pmol . kg-1 . min-1. None of the other polypeptides, however, influenced the resting lower oesophageal sphincter. These studies show that substance P is a potent stimulant of smooth muscle in the lower oesophageal sphincter, suggesting that this peptide may be an important regulator of lower oesophageal sphincter pressure.
D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology; D004943:Esophagogastric Junction / Q000187:drug effects*; D005755:Gastrins / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D011312:Pressure; D013373:Substance P / Q000494:pharmacology; D013552:Swine
D005755:Gastrins; D018377:Neurotransmitter Agents; D010455:Peptides; D013373:Substance P; D002766:Cholecystokinin