The role of nitric oxide in the electrical field stimulation-induced contractions of sphincter of oddi and gallbladder strips in Guinea pigs.
J Pharmacol Sci
; 101(3): 240-4, 2006 Jul.
Article
em En
| MEDLINE
| ID: mdl-16861823
ABSTRACT
The aim of this study was to investigate the modulatory role of nitric oxide (NO) in the electrical field stimulation (EFS)-induced contractions of isolated sphincter of Oddi (SO) and gallbladder strips from guinea pigs. EFS was used to activate the intrinsic nerves in SO and gallbladder strips. EFS produced frequency-dependent biphasic contractile responses in the SO strips. A smaller contraction, "on response", occurred during EFS, which was followed by a bigger contraction, "off response". Both responses were completely and irreversibly abolished by tetrodotoxin (TTX) (10(-6) M). Atropine (10(-6) M) inhibited the "on response", but not the "off response". EFS produced frequency-dependent monophasic contractile responses in gallbladder strips, which were completely and irreversibly abolished by TTX (10(-6) M) and atropine (10(-6) M). A nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine (10(-4) M and 3 x 10(-4) M, in SO and gallbladder strips, respectively), significantly increased all EFS-induced contractions of SO and gallbladder strips. L-Arginine, but not D-arginine reversed the effect induced by the NOS inhibitor, at all frequencies, in both strips. These results suggested that NO released from nitrergic nerve endings might play a regulatory role in the cholinergic neurotransmission of guinea pig SO and gallbladder strips. The "off response" in he SO preparations might be a rebound increase that was modulated by the nonadrenergic, noncholinergic inhibitory mediator NO.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neurônios Nitrérgicos
/
Vesícula Biliar
/
Contração Muscular
/
Músculo Liso
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Óxido Nítrico
/
Esfíncter da Ampola Hepatopancreática
Limite:
Animals
Idioma:
En
Revista:
J Pharmacol Sci
Assunto da revista:
FARMACOLOGIA
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Turquia