Efeito da vasopressina em artérias coronárias epicárdicas caninas. Experimentos sobre a produção de óxido nítrico mediante a estimulação de receptores V1 / Effect of arginine vasopressin on the canine epicardial coronary artery. Experiments on V1-receptor-mediated production of nitric oxide
Arq. bras. cardiol
;
80(5): 483-494, May 2003. ilus, graf
Article
Dans Anglais, Portugais
| LILACS
| ID: lil-336446
ABSTRACT
OBJECTIVE:
To determine whether arginine vasopressin releases endothelium-derived nitric oxide (EDNO) from the epicardial coronary artery.METHODS:
We studied segments of canine left circumflex coronary arteries suspended in organ chambers to measure isometric force. The coronary artery segments were contracted with prostaglandin F2alpha (2 x 10-6M) and exposed to a unique, strong arginine vasopressin concentration (10-6M) or titrated concentrations (10-9 a 10-5 M).RESULTS:
The unique dose of arginine vasopressin concentration (10-6M) induced transient, but significant (p<0.05), relaxation in arterial segments with endothelium, and an increase, not significant, in tension in arteries without endothelium. Endothelium-dependent relaxation to arginine vasopressin was inhibited by Ng-monomethyl-L-arginine (L-NMMA, 10-5M) or N G-nitro-L-arginine (L-NOARG) (10-4M), 2 inhibitors of nitric oxide synthesis from L-arginine. Exogenous L-arginine (10-4M), but not D-arginine (10-4M), reversed the inhibitory effect of L-NMMA on vasopressin-mediated vasorelaxation. Endothelium dependent relaxation to vasopressin was also reversibly inhibited by the vasopressin V1-receptor blocker d(CH2)5Try(Me) arginine vasopressin (10-6M) (n=6, P<0.05).CONCLUSION:
Vasopressin acts through V1 endothelial receptors to stimulate nitric oxide release from L-arginine
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Péricarde
/
Vasoconstricteurs
/
Arginine vasopressine
/
Récepteurs à la vasopressine
/
Vaisseaux coronaires
/
Monoxyde d'azote
Limites du sujet:
Animaux
langue:
Anglais
/
Portugais
Texte intégral:
Arq. bras. cardiol
Thème du journal:
Cardiologie
Année:
2003
Type:
Article
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