Glyceryl dinitrate and ethylene glycol dinitrate caused dose-dependent relaxation of bovine mesenteric artery correlated with increased cGMP levels, supporting cGMP as a mediator of relaxation.
Do organic nitro esters induce vascular smooth muscle relaxation mediated by an increase in cGMP in histamine-contracted bovine mesenteric artery?
The study provides evidence that cGMP acts as a mediator of vascular smooth muscle relaxation induced by organic nitro compounds.
Three different nitro compounds glyceryl mononitrate (GMN), glyceryl dinitrate (GDN) and ethylene glycol dinitrate (EGDN) were tested on histamine contracted bovine mesenteric artery. GDN and EGDN caused a dose-dependent relaxation which was accompanied by an increase in the endogenous cGMP level. The ED50-value for GDN and EGDN with regard to the relaxant action was 1.06 X 10(-6) M and 4.20 X 10(-8), respectively. GMN was almost completely ineffective as a relaxing agent and did not cause any significant change in cGMP. Regression analysis revealed a significant correlation between relaxation and increase in cGMP for both GDN and EGDN. The regression model for EGDN could be significantly improved by including the squared cGMP change, indicating a non-linear relationship. With regard to GDN a hyperbolic relationship between relaxation and cGMP increase was found. A slight improvement of the regression model was found for EGDN when the change in cAMP was included. For GMN and GDN no improvement of the regression model could be revealed by including the change of cAMP. It is suggested that the present data give further evidence for cGMP as a mediator of vascular smooth muscle relaxation induced by nitro compounds.
Axelsson et al. (Thu,) conducted a other in Histamine contracted bovine mesenteric artery. Nitro compounds (glyceryl mononitrate, glyceryl dinitrate, ethylene glycol dinitrate) was evaluated on Vascular smooth muscle relaxation and increase in endogenous cGMP level. Glyceryl dinitrate and ethylene glycol dinitrate caused dose-dependent relaxation of bovine mesenteric artery correlated with increased cGMP levels, supporting cGMP as a mediator of relaxation.