The improvement of the contractile response to angiotensin II in rabbit aorta was inhibited by indomethacin.

S. JEREZ, M.PERAL Y A.COVIELLO

Mendoza

Congreso; XXXII Reunión Anual de la Sociedad Argentina de Farmacología Experimental y XXII Reunión Anual de la Sociedad de Farmacología de Chile; 2000

Sociedad Argentina de Farmacología Experimental y Sociedad de Farmacología de Chile

In previous studies we found that the maximal response (Max.R) to angiotensin II (ang II) in rabbit aortic rings was increased in arteries without endothelium and unchanged in arteries with endothelium (E+) after 90 min. washing with Krebs solution. The aim of present work was to study the interaction between endothelium factors like nitric oxide (NO) and prostaglandin (PG) that may be involved in this phenomena.  Rabbit aortic rings E+ were mounted to register isometric tension. Two cumulative doses response curves (CDRC) to ang II between 90 min. washing were performed. L-NAME 10-4 M, D-NAME 10-4 M or indomethacin 10-5 M was added 30 min. before the first CDRC and maintained during the whole experiment. Other group was treated with L-NAME plus indomethacin. L-NAME increased the Max.R both in the first and the second CDRC. Indomethacin did not modify ang II-response but was able to inhibit the Max.R effect of L-NAME, and a significant shift to the right in second CDRC was observed. In conclusions, this results suggests that the improvement of the contractile response to ang II by L-NAME may be due to  endothelium-production of constrictor  prostanoid released by NO synthase inbibition  but not in the  basal conditions.