TY - JOUR T1 - Enhanced responses to L-arginine in aortic rings from rats with angiotensin-dependent hypertension. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1 LP - 7 VL - 274 IS - 1 AU - M L Pucci AU - L B Dick AU - K B Miller AU - C J Smith AU - A Nasjletti Y1 - 1995/07/01 UR - http://jpet.aspetjournals.org/content/274/1/1.abstract N2 - We contrasted, in normotensive and hypertensive rats, the effect of L-arginine on isometric tension of phenylephrine-contracted rings of aorta bathed in Krebs' bicarbonate buffer on cyclic guanosine monophosphate content of aortic rings and on blood pressure. L-Arginine had no effect on isometric tension or cyclic guanosine monophosphate content of aortic rings from normotensive controls. Conversely, L-arginine (10(-5)-10(-3) mol/l) induced concentration-dependent relaxation of unrubbed and rubbed rings of thoracic and abdominal aorta and, as well, L-arginine (10(-3) mol/l) increased cyclic guanosine monophosphate in unrubbed and rubbed rings of thoracic aorta taken from hypertensive rats 7 to 14 days after aortic coarctation. Similar relaxations to L-arginine were seen in rings of thoracic and abdominal aorta from rats made hypertensive by infusion of angiotensin II for 7 to 8 days but not in rings of thoracic aorta from rats with aortic coarctation-induced hypertension of 28 to 42 days. Relaxant responses to L-arginine in rings of thoracic aorta from hypertensive rats 7 to 14 days after aortic coarctation were unaffected by pretreatment of rings with dexamethasone (10(-7) mol/l) or L-arginine (10(-4) mol/l) but were blunted by NG-nitro-L-arginine methylester (3 x 10(-4) mol/l) or methylene blue (10(-5) mol/l). Our results suggest that the vasorelaxant effects of L-arginine in aortic rings from hypertensive rats 7 to 14 days after aortic coarctation and 7 to 8 days after commencing angiotensin II infusion are mediated by nitric oxide.(ABSTRACT TRUNCATED AT 250 WORDS) ER -