[Somatostatin promotes spontaneous contractions of small intestinal circular muscle via activation of subtype 2 somatostatin receptors in myenteric nerve plexus of macaque intestine].
OBJECTIVE
To investigate the mechanism behind the inhibitive effect of somatostatin (SST) on the intestinal migrating contraction in vivo by observing the effect of SST on spontaneous contractions of the circular muscle of the isolated small intestine and visualizing SST and SST receptor 2 (SSTR2) in the intestinal muscle.


METHODS
Transverse segments of macaque intestine from laparotomy, were mounted in a perfusion system. The effects of SST on their phasic contractions were recorded. SST and SSTR2 in the intestinal muscles of macaque were visualized by immunohistochemical staining and hybridization in situ.


RESULTS
SST (1 x 10(-7) mol/L to 1 x 10(-4) mol/L) significantly increased the frequency of phasic contractions, in a dose-dependent manner, r = 0.984, P < 0.05; (8.33 +/- 1.53) times/min (SST 1 x 10(-7) mol/L) vs (2.67 +/- 0.58) times/min (blank control), P < 0.05. The contractive amplitudes of the isolated circular muscle were also enhanced with the increasing concentration of SST range from 1 x 10(-7) mol/L to 1 x 10(-5) mol/L, r = 0.991, P < 0.05. Both SST and SSTR2 were localized in myenteric nerve plexus between the longitudinal and the circular muscle of the macaque intestine.


CONCLUSIONS
SST directly promoted spontaneous contractions of the circular muscle of macaque intestine via mediation of SSTR2 in myenteric nerve plexus between the longitudinal and the circular muscle. It is contributed to the inhibitive effect of SST on the intestinal migrating contractions.
Li
Dan-Dan
DD
Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu 610041, China.
Chen
Ping
P
Guo
Mei-Mei
MM
Tang
Cheng-Wei
CW
D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000187:drug effects; D008253:Macaca mulatta; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009197:Myenteric Plexus / Q000378:metabolism / Q000502:physiology*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology*
D017481:Receptors, Somatostatin; D013004:Somatostatin