Relación entre la relajación mediada por óxido nítrico y el grado de tono desarrollado durante la contracción isométrica.

JEREZ S, SIERRA L Y PERAL DE BRUNO M.

Tucumán, Tafi del Valle

Congreso; XXII Jornadas Anuales de la Sociedad de Biología de Tucumán.; 2005

Sociedad de Biología de Tucumán

Endotelial release of nitric oxide (NO) may be due to agonist or mechanic stimulation. The aim of this work was to study whether the tone degree developed during agonist stimulation would act as a NO release-mechanic stimulus. Cumulative doses response curves (CDRC) or single stimulations with noradrenaline (NA) at increased doses were performed in rabbit aortic rings. When the maximal response (R.Max) was achieved, acethylcholine (Ach) 10-6 M or sodium nitroprussiate (SN) 10-5 M were added. The % of relaxation to Ach after CDRC was smaller than the % of relaxation after single stimulations (p<0.05, ANOVA). The more the tone degree was, the higher the % of relaxation to Ach was. However, when the tone degree was close to the R.Max the % of relaxation to Ach was smaller (p<0.05, ANOVA with Duncan test). There were no differences in the % of relaxation to SN. These results would indicate the presence of a relationship between the degree of tone developed during the agonist stimulation and the relaxation induced by endothelial release of NO.