| Autor: |
Onori, Luciano, Aggio, Annalisa, Taddei, Gennaro, Loreto, Maria F., Ciccocioppo, Rachele, Vicini, Riccardo, Tonini, Marcello |
| Předmět: |
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| Zdroj: |
American Journal of Physiology: Gastrointestinal & Liver Physiology; Aug2003, Vol. 285 Issue 2, pG325, 7p, 7 Graphs |
| Abstrakt: |
In the gastrointestinal tract, tachykinin NK[sub 1] 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 NK[sub 1] receptors in the regulation of peristalsis is not known. The selective NK[sub l]-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[sup ω]-nitro-L-arginine (L-NNA), a nitric oxide synthase inhibitor, indicating that NK[sub 1] 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 NK[sub 1]-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 NK[sub 1] receptors. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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