Effect of cholecystokinin and secretin on contractile activity of isolated gastric muscle strips in guinea pigs

摘要

AIM To study the effect of cholecystokinin-octapeptide（CCK-8）and secretin on contractileactivity of isolated gastric muscle strips inguinea pigs.METHODS Each isolated gastric muscle stripwas suspended in a tissue chamber containing5 mL Krebs solution constantly warmed by waterjacked at 37℃ and supplied with a mixed gas of95% O2 and 5% CO2 After incubating for lhunder 1 g tension,varied concentrations of CCK-8 and secretin were added respectively in thetissue chamber and the contractile response wasmeasured isometrically on ink-writing recorders.RESULTS CCK-8 could increase①all regionalcircular and longitudinal muscular tension at rest（fundus LM 19.7%±2.1%,P0.01;fundus CM16.7%±2.2%,P0.01;gastric body LM 16.8%±2.3%,P0.01;body CM 12.7%±2.6%,P0.01;antrum LM 12.3%±1.3%,P0.01;antrum CM 16.7%±4.5%,P0.01;pylous CM12.7%±5.0%,P0.05）;②contractilefrequencies of body LM,both LM and CM ofantrum and pylorus CM（5.1/min±0.2/min to5.6/min±0.2/min,5.9/min±0.2/min to 6.6/min±0.l/min,5.4/min±0.3/min to 6.3/min±0.4/rain,1.3/min±0.2/min to 2.3/min±0.3/min,respectively,P0.05）;③the mean contractileamplitude of antral circular muscle（58.6%±18.4%,P0.05）and ④the motility index ofpylorus CM（145.0%±23.8%,P0.01）,butdecrease the mean contractile amplitude ofgastric body and antral LM（-10.3%±3.3%,-10.5%±4.6%,respectively,P0.05）.All the CCK-8 effects were not blocked by atropine orindomethacin.Secretin had no effect on gastricsmooth muscle activity.CONCLUSION CCK-8 possessed bothexcitatory and inhibitory action on contractileactivity of different regions of stomach in guineapigs.Its action was not mediated via cholinergicM receptor and endogenous prostagiandinreceptor,