Action of the newly discovered mammalian tachykinins, substance K and neuromedin K, on gastroduodenal motility of anesthetized dogs.
The present experiments examined the local effects of two new mammalian tachykinins isolated from porcine spinal cord, substance K and neuromedin K, on gastroduodenal motility of anesthetized dogs. Tachykinins were injected through the gastroepiploic and cranial pancreaticoduodenal arteries at concentrations ranging from 1 to 100 ng/ml. Substance K, neuromedin K and substance P increased gastroduodenal smooth muscle contractions in a dose-dependent manner. The contractile response of the gastric antrum to newly discovered tachykinins was not as long-lasting as that to substance P. The potencies of various tachykinins on contractile responses showed the following rank order of potencies: physalaemin = eledoisin = substance P greater than substance K = neuromedin K in gastric smooth muscle; physalaemin = substance P = eledoisin greater than substance K = neuromedin K in the duodenal smooth muscle. Administration of atropine (100-200 micrograms/kg) inhibited the effect of tachykinins both in the gastric antrum and in the proximal duodenum. These results indicate that substance K and neuromedin K could act as transmitters or as modulators of neuronal activity influencing gastroduodenal motility.
D000818:Animals; D004285:Dogs; D004386:Duodenum / Q000502:physiology; D004600:Eledoisin / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects; D015288:Neurokinin A; D015287:Neurokinin B; D009479:Neuropeptides / Q000494:pharmacology*; D010803:Physalaemin / Q000494:pharmacology; D013270:Stomach / Q000502:physiology; D013373:Substance P / Q000494:pharmacology; D015320:Tachykinins
D009479:Neuropeptides; D015320:Tachykinins; D010803:Physalaemin; D013373:Substance P; D004600:Eledoisin; D015288:Neurokinin A; D015287:Neurokinin B