ACh-evoked membrane hyperpolarization in smooth muscle cells of rat vas deferens in vitro: involvement of K(+) channels and NO / 生理学报
Acta Physiologica Sinica
; (6): 331-338, 2007.
Article
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| ID: wpr-258648
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ABSTRACT
To explore the underlying mechanism of acetylcholine (ACh)-evoked membrane hyperpolarizing response in isolated rat vas deferens smooth muscle cells (SMCs), intracellular microelectrode recording technique and intracellular microelectrophoresis fluorescent staining technique were used to study ACh-evoked membrane hyperpolarizing response in SMCs freshly isolated from Wistar rat vas deferens. By using microelectrodes containing fluorescent dye 0.1% propidium iodide (PI), 37 and 17 cells were identified as SMCs in outer longitudinal and inner circular muscular layers, respectively. The resting membrane potentials of SMCs were (-53.56+/-3.88) mV and (-51.62+/-4.27) mV, respectively. The membrane input resistances were (2245.60+/-372.50) MOmega and (2101.50+/-513.50) MOmega, respectively. ACh evoked membrane hyperpolarizing response in a concentration-dependent manner with an EC(50) of 36 micromol/L. This action of ACh was abolished by both a non-sepcific muscarinic (M) receptor antagonist atropine (1 mumol/L) and a selective M(3 ) receptor antagonist diphenylacetoxy-N-methylpiperidine-methiodide (DAMP, 100 nmol/L). ACh-evoked membrane hyperpolarization was also abolished by a nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME, 300 micromol/L) and suppressed by an ATP-sensitive potassium (K(ATP)) channel blocker glipizide (5 micromol/L) and an inward rectifier potassium (K(ir)) channel inhibitor bariumion (50 micromol/L). A combination of glipizide and bariumion abolished ACh-evoked membrane hyperpolarizing response. The results suggest that ACh-evoked membrane hyperpolarization in rat vas deferens SMCs is mediated by M(3) receptor followed with activation of K(ATP) channels, K(ir) channels, and NO release.
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Assunto principal:
Farmacologia
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Fisiologia
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Ducto Deferente
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Técnicas In Vitro
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Canais de Potássio
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Acetilcolina
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Ratos Wistar
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Canais de Potássio Corretores do Fluxo de Internalização
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Miócitos de Músculo Liso
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Glipizida
Limite:
Animals
Idioma:
En
Revista:
Acta Physiologica Sinica
Ano de publicação:
2007
Tipo de documento:
Article