Activation of neural cholecystokinin-1 receptors induces relaxation of the isolated rat duodenum which is reduced by nitric oxide synthase inhibitors
Braz. j. med. biol. res
;
39(2): 271-275, Feb. 2006. ilus
Artigo
em Inglês
| LILACS
| ID: lil-420279
ABSTRACT
Cholecystokinin (CCK) influences gastrointestinal motility, by acting on central and peripheral receptors. The aim of the present study was to determine whether CCK has any effect on isolated duodenum longitudinal muscle activity and to characterize the mechanisms involved. Isolated segments of the rat proximal duodenum were mounted for the recording of isometric contractions of longitudinal muscle in the presence of atropine and guanethidine. CCK-8S (EC50 39; 95 percent CI 4.1-152 nM) and cerulein (EC50 58; 95 percent CI 18-281 nM) induced a concentration-dependent and tetrodotoxin-sensitive relaxation. Nomeganitro-L-arginine (L-NOARG) reduced CCK-8S- and cerulein-induced relaxation (IC50 5.2; 95 percent CI 2.5-18 æM) in a concentration-dependent manner. The magnitude of 300 nM CCK-8S-induced relaxation was reduced by 100 æM L-NOARG from 73 ± 5.1 to 19 ± 3.5 percent in an L-arginine but not D-arginine preventable manner. The CCK-1 receptor antagonists proglumide, lorglumide and devazepide, but not the CCK-2 receptor antagonist L-365,260, antagonized CCK-8S-induced relaxation in a concentration-dependent manner. These findings suggest that CCK-8S and cerulein activate intrinsic nitrergic nerves acting on CCK-1 receptors in order to cause relaxation of the rat duodenum longitudinal muscle.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Fragmentos de Peptídeos
/
Ceruletídeo
/
Colecistocinina
/
Receptores da Colecistocinina
/
Óxido Nítrico Sintase
/
Duodeno
/
Contração Muscular
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2006
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade de São Paulo/BR
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