Wang Fang, Zheng Tian-Zhen, Li Wei, Qu Song-Yi, He Di-Ying
Insititute of Infectious Diseases, the Third Military Medical University Afflicated Southwest Hospital, Chongqing 400038, China.
World J Gastroenterol. 2003 Apr;9(4):775-8. doi: 10.3748/wjg.v9.i4.775.
To study the effect of progesterone on contractile activity of isolated gastric strips in rats.
Wistar rats were sacrificed to remove whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to either the circular or the longitudinal fibers, muscle strips were cut from fundus, body, antrum and pylorus. Each muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution. Then the motility of gastric strips in tissue chambers was simultaneously recorded. The preparations were subjected to 1 g load tension and washed with 5 ml Krebs solution every 20 min. After 1 h equilibration, progesterone or antagonists were added in the tissue chamber separately. The antagonists were added 3 min before using progesterone (50 micromol/L(-1)).
Progesterone decreased the resting tension of fundus and body longitudinal muscle (LM) (P<0.05). It inhibited the mean contractile amplitude of body and antrum LM and circular muscle (CM), and the motility index of pyloric CM (P<0.05). The inhibition of progesterone on the mean contractile amplitude could be partially blocked by phentolamine in LM of the stomach body (the mean contractile amplitude of body LM decreased from -7.5+/-5.5 to -5.2+/-4.5 P<0.01), and by phentolamine or indomethacin in CM of body (The inhibition of progesterone on the mean contractile amplitude of body CM decreased from -5.6+/-3.0 to -3.6+/-2.7 by phentolamine and from -5.6+/-3.0 to -3.5+/-2.5 by indomethacin, P<0.01). Hexamethonium, propranolol and L-NNA (inhibitor of NO synthetase) didn't affect the action of progesterone (P>0.05).
The study suggested that progesterone can inhibit the contractile activity of isolated gastric strips in rats and the mechanism seems to be a direct one except that the action on gastric body is mediated through prostaglandin and adrenergic alpha receptor partly.
研究孕酮对大鼠离体胃条收缩活动的影响。
处死Wistar大鼠，取出整个胃。然后打开胃，去除黏膜层。与环行或纵行纤维平行，从胃底、胃体、胃窦和幽门切取肌条。将每条肌条悬挂于含有5 mL Krebs溶液的组织浴槽中。然后同时记录组织浴槽中胃条的运动情况。标本施加1 g负荷张力，每20分钟用5 ml Krebs溶液冲洗一次。平衡1小时后，分别向组织浴槽中加入孕酮或拮抗剂。拮抗剂在使用孕酮（50 μmol/L(-1)）前3分钟加入。
孕酮降低了胃底和胃体纵行肌（LM）的静息张力（P<0.05）。它抑制了胃体和胃窦LM及环行肌（CM）的平均收缩幅度，以及幽门CM的运动指数（P<0.05）。孕酮对平均收缩幅度的抑制作用在胃体LM可被酚妥拉明部分阻断（胃体LM的平均收缩幅度从-7.5±5.5降至-5.2±4.5，P<0.01），在胃体CM可被酚妥拉明或吲哚美辛阻断（酚妥拉明使孕酮对胃体CM平均收缩幅度的抑制作用从-5.6±3.0降至-3.6±2.7，吲哚美辛使其从-5.6±3.0降至-3.5±2.5，P<0.01）。六甲铵、普萘洛尔和L-NNA（一氧化氮合酶抑制剂）不影响孕酮的作用（P>0.05）。
该研究表明孕酮可抑制大鼠离体胃条的收缩活动，其机制似乎是直接作用，除了对胃体的作用部分通过前列腺素和肾上腺素能α受体介导。
