Functional and immunocytochemical evidence that galanin is a physiologicalregulator of human jejunal motility

Citation
A. Balint et al., Functional and immunocytochemical evidence that galanin is a physiologicalregulator of human jejunal motility, J PHYSL-PAR, 95(1-6), 2001, pp. 129-135
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
JOURNAL OF PHYSIOLOGY-PARIS
ISSN journal
0928-4257 → ACNP
Volume
95
Issue
1-6
Year of publication
2001
Pages
129 - 135
Database
ISI
SICI code
0928-4257(200101/12)95:1-6<129:FAIETG>2.0.ZU;2-J
Abstract
The neuropeptide galanin has species-dependent effects on intestinal motili ty. It has a contractile effect on rat jejunal muscle while it relaxes guin ea-pig ileum by inhibiting cholinergic transmission. Its effect on human gu t motility has been unknown. Extensive work led to the discovery of selecti ve galanin analogues such as M 15 [galanin(1-12)-Pro-substance-P(5-11)], M3 5 [galanin(1-12)-Pro-bradykinin(2-9)-aniide] that competitively inhibit var ious actions of galanin in the central nervous system. The present study wa s designed to examine the effect of galanin, M 15 and M35 on longitudinal j ejunal smooth muscle strips isolated from humans and rats, and to localize galanin-immunoreactivity in human jejunum. Galanin and ACh were equally eff ective in stimulating contractions of the isolated jejunal muscle: sigmoid curve fitting showed that maximal contractile response to galanin and ACh w ere 25.7 +/- 11.1 mN and 23.7 +/-9.7 in humans, while 8.0 +/-0.6 and 8.1 +/ -0.3 mN in rats. respectively. These effects of galanin were not inhibited by either atropine (5x10(-6) M) or tetrodotoxin (3 x 10(-6) M). The potency of galanin inducing the contractile actions were similar in humans and rat s. Interestingly, neither M15 nor M35 (up to 10(-7) M) were able to inhibit the responses of the smooth muscle to galanin. However, both putative gala nin receptor antagonists showed agonist effects in our experimental models. In accordance with the functional studies, both the longitudinal and the c ircular muscle layers were abundant in nerve fibers and varicosities showin g galanin immunoreactivity. Our data suggest that galanin is a potent physi ological regulator of jejunal contractions in humans. Its action on the jej unum, however, is mediated by galanin receptors that are different from tho se located in the central nervous system. (C) 2001 Elsevier Science Ltd. Al l rights reserved.