Journal article

Publication year: 2013

Pages: E581-E590

Journal: Neurogastroenterology and Motility

Volume number: 25

Issue number: 9

ISSN: 1350-1925

DOI Link: https://doi.org/10.1111/nmo.12165

Publisher: Wiley: 12 months

Abstract: 

Background
In rat duodenum, bradykinin induces a relaxation followed by a contraction. Different types of ion channels and receptors as well as non-muscle cells have been suggested to be involved in this response. As it is unclear whether these changes are observed also in rat large intestine and the mechanisms which might underlie this response, the effect of bradykinin on rat colonic motility was tested. 

Methods
Isometric contractions were measured on full-thickness preparations or preparations, from which individual layers had been dissected. The expression of bradykinin receptors was analyzed by immunohistochemistry and RT-PCR. Isolated intestinal muscle cells were investigated with Ca2+-imaging techniques. 

Key Results
Bradykinin caused a biphasic contractile response 9initial relaxation followed by contraction) in rat colon, which was resistant against tetrodotoxin. The kinin-induced relaxation was inhibited by tetrapentylammonium chloride, a blocker of Ca2+-activated K+ channels. Des-arg 9 -bradykinin did not induce any effect on the native colon, although after 5 h in vitro preincubation, a contractile response was evoked by this B-1 receptor agonist. The consecutive ablation of adherent layers of the intestinal wall strongly reduced the response to bradykinin in comparison with a control stimulus, i. e., carbachol, suggesting a contribution of non-muscle cells in the mediation of this response. 

Conclusions & Inferences
Bradykinin induced a biphasic change in contractility in the rat colon. In the native intestine, only the B-2 receptor is involved in this effect. Neighboring cell obviously sensitize the smooth muscle to the stimulation of these receptors.

Harvard Citation style: Würner, L. and Diener, M. (2013) Receptors and mechanisms mediating the biphasic response evoked by bradykinin in rat colonic smooth muscle, Neurogastroenterology and Motility, 25(9), pp. E581-E590. https://doi.org/10.1111/nmo.12165

APA Citation style: Würner, L., & Diener, M. (2013). Receptors and mechanisms mediating the biphasic response evoked by bradykinin in rat colonic smooth muscle. Neurogastroenterology and Motility. 25(9), E581-E590. https://doi.org/10.1111/nmo.12165