We have located links that may give you full text access.
Bidirectional regulation of human colonic smooth muscle contractility by tachykinin NK(2) receptors.
In this study, we attempted to clarify the mechanism of tachykinin-induced motor response in isolated smooth muscle preparations of the human colon. Fresh specimens of normal colon were obtained from patients suffering from colonic cancer. Using mucosa-free smooth muscle strips, smooth muscle tension with circular direction was monitored isometrically. Substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) produced marked contraction. All of these contractions were inhibited by saredutant, a selective NK(2)-R antagonist, but not by CP122721, a selective NK(1)-R antagonist or talnetant, a selective NK(3)-R antagonist. βAla(8)-NKA(4-10) induced concentration-dependent contraction similar to NKA, but Sar(9)-Met(11)-SP and Met-Phe(7)-NKB did not cause marked contraction. Colonic contraction induced by βAla(8)-NKA(4-10) was completely blocked by saredutant, but not by atropine. Tetrodotoxin or N(G)-nitro-L-arginine methyl ester pretreatment significantly enhanced βAla(8)-NKA(4-10)-induced contraction. Immunohistochemical analysis showed that the NK(2)-R was expressed on the smooth muscle layers and myenteric plexus where it was also co-expressed with neuronal nitric oxide synthase in the myenteric plexus. These results suggest that the NK(2)-R is a major contributor to tachykinin-induced smooth muscle contraction in human colon and that the NK(2)-R-mediated response consists of an excitatory component via direct action on the smooth muscle and an inhibitory component possibly via nitric oxide neurons.
Full text links
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app