I. Rubinstein et Wg. Mayhan, L-ARGININE DILATES CHEEK POUCH ARTERIOLES IN HAMSTERS WITH HEREDITARYCARDIOMYOPATHY BUT NOT IN CONTROLS, The Journal of laboratory and clinical medicine, 125(3), 1995, pp. 313-318
Citations number
25
Categorie Soggetti
Medical Laboratory Technology","Medicine, General & Internal
The purpose of this study was to determine whether suffusion of L-argi
nine alone induces vasodilation in the cheek pouch of hamsters with he
reditary cardiomyopathy in comparison with controls, and whether these
effects are mediated by the L-arginine/nitric oxide biosynthetic path
way. Using intravital microscopy, we found that suffusion of L-arginin
e for 20 minutes induced a significant, stereospecific concentration-d
ependent vasodilation in hamsters with hereditary cardiomyopathy but n
ot in controls (p < 0.05). These responses were abrogated by suffusion
of the nitric synthase inhibitor N-G-L-arglnine methyl ester (L-NAME)
but not by suffusion of D-NAME. Suffusion of nitroglycerin, a nitric
oxide donor, induced significant vasodilation of similar magnitude in
both groups (p < 0.05). L-NAME had no significant effects on nitroglyc
erin-induced responses in both groups. We conclude that direct applica
tion of L-arginine alone to the peripheral microcirculation in cardiom
yopathy induces significant vasodilation that is mediated, most likely
, via a nitric oxide-dependent mechanism(s). We suggest that a reversi
ble, L-arginine- responsive impairment in the constitutive L-arginine/
nitric oxide biosynthetic pathway is present in the peripheral microci
rculation in cardiomyopathy.