Effects of Polyamines on Contractility of Guinea-Pig Gastric Smooth Muscle.
10.3346/jkms.2007.22.1.48
- Author:
Young Chul KIM
1
;
Jae Hoon SIM
;
Young Ho KIM
;
Seong Chun KWON
;
Sang Jin LEE
;
Seung Ryul KIM
;
Dong Woon KIM
;
Seon Mee PARK
;
Sei Jin YOUN
;
Sang Jeon LEE
;
De Gang XING
;
Wen Xie XU
;
Ki Whan KIM
Author Information
1. Department of Physiology, Chungbuk National University, College of Medicine, Cheongju, Korea. physiokyc@chungbuk.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Muscle, Smooth;
myocytes, Smooth Muscle;
Gastrointestinal Tract;
Calcium Current;
Polyamines;
Spermine;
Spermidine;
Putrescine
- MeSH:
Pyloric Antrum/*drug effects/physiology;
Potassium/pharmacology;
Polyamines/*pharmacology;
Muscle, Smooth/*drug effects/physiology;
Muscle Contraction/*drug effects;
Male;
Guinea Pigs;
Female;
Calcium Channels/drug effects/physiology;
Calcium/metabolism;
Animals
- From:Journal of Korean Medical Science
2007;22(1):48-56
- CountryRepublic of Korea
- Language:English
-
Abstract:
This study was designed to investigate the effects of polyamines on mechanical contraction and voltage-dependent calcium current (VDCC) of guinea-pig gastric smooth muscle. Mechanical contraction and calcium channel current (I(Ba)) were recorded by isometric tension recording and whole-cell patch clamp technique. Spermine, spermidine and putrescine inhibited spontaneous contraction of the gastric smooth muscle in a concentration-dependent manner. Spermine (2 mM) reduced high K+ (50 mM)-induced contraction to 16+/-6.4% of the control (n=9), and significantly inhibited I(Ba) in a reversible manner (p<0.05; IC50=0.8 mM). Pre- and post-treatment of tissue with spermine (2-5 mM, n=10) also inhibited acetylcholine (10 micrometer)-induced phasic contraction to 5+/-6.4% of the control. Inhibitory effect of spermine on I(Ba) was observed at a wide range of test potentials of current/voltage (I/V) relationship (p<0.05), and steady-state activation of I(Ba) was shifted to the right by spermine (p<0.05). Spermidine and putrescine (1 mM each) also inhibited I(Ba) to 51+/-5.7% and 81+/-5.3% of the control, respectively. And putrescine (1 mM) inhibited I(Ba) at whole tested potentials (p<0.05) without significant change of kinetics (p<0.05). Finally, 5 mM putrescine also inhibited high K+ -induced contraction to 53+/-7.1% of the control (n=4). These findings suggest that polyamines inhibit contractions of guinea-pig gastric smooth muscle via inhibition of VDCC.
