Xie Dong-Ping, Chen Lian-Bi, Liu Chuan-Yong, Liu Jing-Zhang, Liu Ke-Jing
Department of Physiology, School of Medicine, Shandong University, Jinan 250012, Shandong Province, China.
World J Gastroenterol. 2003 Jan;9(1):165-8. doi: 10.3748/wjg.v9.i1.165.
To investigate the effects of oxytocin (OT) on isolated rabbit proximal colon and its mechanism.
Both longitudinal muscle (LM) and circular muscle (CM) were suspended in a tissue chamber containing 5 mL Krebs solution (37 degrees ), bubbled continuously with 950 mL x L(-1) O(2) and 50 mL x L(-1) CO(2). Isometric spontaneous contractile responses to oxytocin or other drugs were recorded in circular and longitudinal muscle strips.
OT (0.1 U x L(-1)) failed to elicit significant effects on the contractile activity of proximal colonic smooth muscle strips (P>0.05). OT (1 to 10 U x L(-1)) decreased the mean contractile amplitude and the contractile frequency of CM and LM. Hexamethonium (10 micromol x L(-1)) partly blocked the inhibition of oxytocin (1 U x L(-1)) on the contractile frenquency of CM. N(omega))-nitro-L-arginine-methylester (L-NAME, 1 micromol x L (-1)), progesterone (32 micromol x L(-1)) and estrogen (2.6 micromol x L(-1)) had no effects on OT-induced responses.
OT inhibits the motility of proximal colon in rabbits. The action is partly relevant with N receptor, but irrelevant with that of NO, progesterone or estrogen.
研究催产素（OT）对离体兔近端结肠的作用及其机制。
将纵行肌（LM）和环行肌（CM）悬挂于含有5 mL Krebs溶液（37℃）的组织浴槽中，持续通入950 mL/L O₂和50 mL/L CO₂。记录环行肌和纵行肌条对催产素或其他药物的等长自发收缩反应。
OT（0.1 U/L）对近端结肠平滑肌条的收缩活性无显著影响（P>0.05）。OT（1～10 U/L）降低了CM和LM的平均收缩幅度和收缩频率。六甲铵（10 μmol/L）部分阻断了催产素（1 U/L）对CM收缩频率的抑制作用。Nⁿ-硝基-L-精氨酸甲酯（L-NAME，1 μmol/L）、孕酮（32 μmol/L）和雌激素（2.6 μmol/L）对OT诱导的反应无影响。
OT抑制兔近端结肠的运动。该作用部分与N受体有关，但与一氧化氮、孕酮或雌激素无关。
