Original Articles
Copyright ©The Author(s) 2000. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 15, 2000; 6(1): 93-95
Published online Feb 15, 2000. doi: 10.3748/wjg.v6.i1.93
Effect of cholecystokinin and secretin on contractile activity of isolated gastric muscle strips in guinea pigs
Wei Li, Tian-Zhen Zheng, Song-Yi Qu
Wei Li, Tian-Zhen Zheng, Song-Yi Qu, Department of Physiology, Lanzhou Medical College, Lanzhou 730000, Gansu Province, China
Wei Li, female, born on 1952-06-07 in Taiyuan, Shanxi Province, graduated from Lanzhou Medical College in 1977, now associate Professor of physiology, majoring digestive physiology, having 25 papers published.
Author contributions: All authors contributed equally to the work.
Correspondence to: Wei Li, Department of Physiology, Lanzhou Med ical College, Lanzhou 730000, Gansu Province, China.
Telephone: +86-931-8289531
Received: May 30, 1999
Revised: August 22, 1999
Accepted: September 11, 1999
Published online: February 15, 2000
Abstract

AIM: To study the effect of cholecystokinin-octapeptide (CCK- 8) and secretin on contractile activity of isolated gastric muscle strips in guinea pigs.

METHODS: Each isolated gastric muscle strip was suspended in a t issue chamber containing 5 mL Krebs solution constantly warmed by water jacked at 37 °C and supplied with a mixed gas of 95% O2 and 5% CO2. After incubating for 1h under 1g tension, varied concentrations of CCK-8 and se cretin were added respectively in the tissue chamber and the contractile response was measured isometrically on ink-writing recorders.

RESULTS: CCK-8 could increase ① all regional circular and longitudinal muscular tension at rest (fundus LM 19.7% ± 2.1%, P < 0.01; fundus CM 16.7% ± 2.2%, P < 0.01; gastric body LM 16 .8% ± 2.3%, P < 0.01; body CM 12.7% ± 2.6%, P < 0.01; antrum LM 12.3% ± 1.3%, P < 0.01; antrum CM 16.7% ± 4.5%, P < 0.01; pylous CM 12.7% ± 5.0%, P < 0.05); ② contractile frequencies of body LM, both LM and CM of antrum and pylorus CM (5.1/min ± 0.2/min to 5.6/min ± 0.2/min, 5.9/min ± 0.2/min to 6.6/min ± 0.1/min, 5.4/min ± 0.3/min to 6.3/min ± 0.4/min, 1.3/min ± 0.2/min to 2.3/min ± 0.3/min, respectively, P < 0.05); ③ the mean contractile amplitude of antral circular mus cle (58.6% ± 18.4%, P < 0.05) and ④ the motility index of pylorus CM (145.0% ± 23.8%, P < 0.01), but decrease the mean contractile ampl itude of gastric body and antral LM (-10.3% ± 3.3%, -10.5% ± 4.6%, respectively, P < 0.05). All the CCK-8 effects were not blocked by atropine or ind omethacin. Secretin had no effect on gastric smooth muscle activity.

CONCLUSION: CCK-8 possessed both excitatory and inhibitory action on contractile activity of different regions of stomach in guinea pigs.Its action was not mediated via cholinergic M receptor and endogenous prostaglandin receptor.

Keywords: gastric muscle strips; cholecystokinin; secretin; guinea pigs