{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,6,29]],"date-time":"2025-06-29T05:40:05Z","timestamp":1751175605737,"version":"3.41.0"},"reference-count":30,"publisher":"American Physiological Society","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Gastrointestinal and Liver Physiology"],"published-print":{"date-parts":[[1999,4,1]]},"abstract":"<jats:p>Pregnancy has an inhibitory effect on motility of the gastrointestinal tract. The present study was designed to examine the mechanisms responsible for antral and colonic hypomotility in pregnant guinea pigs. Circular smooth muscle cells from the antrum and left colon were isolated by enzymatic digestion with collagenase from pregnant and nonpregnant guinea pigs. Contractile responses to agonists were expressed as percent shortening from resting cell length. The function of G proteins in antral and colonic circular smooth muscle was assessed by [<jats:sup>35<\/jats:sup>S]guanosine 5\u2032- O-(3-thiotriphosphate) (GTP\u03b3S) binding induced by CCK-8 and G protein quantitation. The contraction of antral and colonic circular smooth muscle from pregnant guinea pigs was reduced in response to CCK-8 and to GTP\u03b3S but was normal in response to KCl andd- myo-inositol 1,4,5-trisphosphate compared with nonpregnant animals. The stimulation of [<jats:sup>35<\/jats:sup>S]GTP\u03b3S binding to G\u03b1<jats:sub>q-11<\/jats:sub>induced by 1 \u03bcM CCK-8 was significantly lower in antral and colonic circular smooth muscle from pregnant guinea pigs than that in controls. Furthermore, Western blot analysis showed a decreased G\u03b1<jats:sub>q-11<\/jats:sub>and an increased G<jats:sub>s<\/jats:sub>\u03b1 protein content in both tissues during pregnancy. It is concluded that pregnancy appears to impair gastrointestinal circular smooth muscle contractility by downregulating G proteins such as G\u03b1<jats:sub>q-11<\/jats:sub>protein, which mediates muscle contraction, and upregulating G<jats:sub>s<\/jats:sub>\u03b1 protein, which mediates muscle relaxation.<\/jats:p>","DOI":"10.1152\/ajpgi.1999.276.4.g895","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T09:46:14Z","timestamp":1514108774000},"page":"G895-G900","source":"Crossref","is-referenced-by-count":10,"title":["Downregulation of G\u03b1<sub>q-11<\/sub>protein expression in guinea pig antral and colonic circular muscle during pregnancy"],"prefix":"10.1152","volume":"276","author":[{"given":"Qian","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Medicine, Rhode Island Hospital and Brown University School of Medicine, Providence, Rhode Island 02903"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zuo-Liang","family":"Xiao","sequence":"additional","affiliation":[{"name":"Department of Medicine, Rhode Island Hospital and Brown University School of Medicine, Providence, Rhode Island 02903"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Piero","family":"Biancani","sequence":"additional","affiliation":[{"name":"Department of Medicine, Rhode Island Hospital and Brown University School of Medicine, Providence, Rhode Island 02903"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jose","family":"Behar","sequence":"additional","affiliation":[{"name":"Department of Medicine, Rhode Island Hospital and Brown University School of Medicine, Providence, Rhode Island 02903"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"24","reference":[{"issue":"22","key":"B1","first-page":"E57","volume":"259","author":"Arkinstall S. 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