Different mechanisms mediate beta adrenoceptor stimulated vasorelaxation of coronary and femoral arteries.
OBJECTIVE
To determine whether different mechanisms mediate vasorelaxation of swine coronary and femoral arteries induced by beta adrenoceptor stimulation.


METHODS
The organ-bath was used to observe the tension changes in rings of coronary and femoral arteries to different concentrations of isoprenaline (ISO) after endothelium removal, nitric-oxide synthase (NOS) inhibition by L-NMMA and beta 1 and/or beta 2 adrenoceptor antagonization.


RESULTS
Endothelium removal, NOS inhibition, beta 2 adrenoceptor antagonization did not change the vasorelaxation induced by ISO in coronary artery, however, abolished the vasorelaxation in femoral artery. beta 1 Adrenoceptor antagonization did not change the tension of femoral artery, but abolished the ISO induced vasorelaxation of coronary artery.


CONCLUSIONS
Vasorelaxing effect of ISO in swine coronary artery is mediated through beta 1 adrenoceptor and not through L-arginine/nitric oxide pathway, however, in femoral artery, it is mediated through beta 2 adrenoceptor and L-arginine/nitric oxide pathway.
Xu
B
B
Department of Cardiology, Affiliated Hospital of Nanjing Railway Medical College, Nanjing 210009, China. njbiaoxu@jlonline.com
Huang
Y
Y
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001158:Arteries / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000037:antagonists & inhibitors; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D011412:Propanolamines / Q000494:pharmacology; D013552:Swine; D014664:Vasodilation / Q000187:drug effects*; D019323:omega-N-Methylarginine / Q000494:pharmacology
D000319:Adrenergic beta-Antagonists; D007093:Imidazoles; D011412:Propanolamines; D019323:omega-N-Methylarginine; C026777:ICI 118551; C049763:CGP 20712A; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D007545:Isoproterenol