Effects of Polyamines on Contractility of Guinea-Pig Gastric Smooth Muscle
Journal of Korean Medical Science
; : 48-56, 2007.
Article
em En
| WPRIM
| ID: wpr-226406
Biblioteca responsável:
WPRO
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.
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Texto completo:
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Base de dados:
WPRIM
Assunto principal:
Poliaminas
/
Potássio
/
Antro Pilórico
/
Canais de Cálcio
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Cálcio
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Cobaias
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Contração Muscular
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Músculo Liso
Limite:
Animals
Idioma:
En
Revista:
Journal of Korean Medical Science
Ano de publicação:
2007
Tipo de documento:
Article