[The mechanism of somatostatin-induced acid secretion inhibition in isolated parietal cells].
OBJECTIVE
So far five different somatostatin receptor(SSR) subtypes have been characterized. Somatostatin has been reported to inhibit acid secretion in vivo, but which subtype of the receptor mediate acid secretion in rabbit is unclear. The aim of this study is to identify which subtype mediates inhibition of acid secretion and to observe the effects of somatostatin and its selective agonists on histamine-stimulated acid secretion by(14)C-aminopyrine((14)C-AP) accumulation.


METHODS
The effect of SS-14 and other receptor subtype agonists on histamine-stimulated acid secretion was studied with(14)C-AP accumulation in pure parietal cells. To identify SSR on parietal cells, positive SSR-specific primers by reverse transcription polymerase chain reaction (RT-PCR) and its probe by in situ hybridization (ISH) were used.


RESULTS
(1) SS-14, sandostatin and SSR2 specific agonist NC8-12 (10(-9)-10(-7) mol/L) significantly inhibited histamine-stimulated (10(-6)) mol/L) acid secretion (P < 0.01), but SSR3 and SSR4 specific agonists had no inhibitory effects on histamine-stimulated acid secretion at the same concentrations(P > 0.05). (2) SSR2 gene expression in parietal cell was demonstrated with both RT-PCR and ISH method.


CONCLUSIONS
The authors verified for the first time that SSR2 mediates the inhibition of histamine-induced acid secretion in parietal cell, and that SSR2 is present on parietal cells.
Li
X
X
Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
Qian
J
J
Chen
Y
Y
Chen
Y
Y
D000818:Animals; D005744:Gastric Acid / Q000378:metabolism*; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits; D017481:Receptors, Somatostatin / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013004:Somatostatin / Q000494:pharmacology*
D017481:Receptors, Somatostatin; D013004:Somatostatin