Peristalsis regulation by tachykinin NK1 receptors in the rabbit isolated distal colon.

Autor: Onori L; Dept. of Internal Medicine and Public Health, Univ. of L'Aquila, Italy. annaggio@katamail.com, Aggio A, Taddei G, Loreto MF, Ciccocioppo R, Vicini R, Tonini M
Jazyk: angličtina
Zdroj: American journal of physiology. Gastrointestinal and liver physiology [Am J Physiol Gastrointest Liver Physiol] 2003 Aug; Vol. 285 (2), pp. G325-31. Date of Electronic Publication: 2003 Mar 26.
DOI: 10.1152/ajpgi.00411.2002
Abstrakt: In the gastrointestinal tract, tachykinin NK1 receptors are widely distributed in a number of neuronal and nonneuronal cells involved in the control of gut motor activity. In particular, in the rabbit isolated distal colon, which is a suitable model system to investigate the contribution of tachykinins as noncholinergic excitatory transmitters, the influence of NK1 receptors in the regulation of peristalsis is not known. The selective NK1-receptor antagonists SR-140333 (0.3 and 1 nM) and MEN-10930 (0.3-10 nM) significantly enhanced the velocity of rabbit colonic propulsion to submaximal stimulation. The prokinetic effect of SR-140333 was prevented by N(omega)-nitro-L-arginine (L-NNA), a nitric oxide synthase inhibitor, indicating that NK1 receptors located on nitrergic innervation exert a functional inhibitory restraint on the circular muscle and probably on descending excitatory and inhibitory pathways during propulsion. Conversely, the selective NK1-receptor agonist septide (3-10 nM) significantly inhibited colonic propulsion. In the presence of L-NNA, the inhibitory effect of septide was reverted into a prokinetic effect, which is probably mediated by the activation of postjunctional excitatory NK1 receptors.
Databáze: MEDLINE