Demonstration of a high affinity component of glyceryl trinitrate induced vasodilatation in the bovine mesenteric artery.
Strips of bovine mesenteric artery mounted in disposable organ baths made of polyethylene showed a biphasic relaxation pattern when exposed to glyceryl trinitrate (GTN). The concentration response curve could be resolved into a high affinity component (pD2 11.9) and a low affinity component (pD2 7.5) by means of non-linear regression analysis. The relaxation induced by both low (0.01 nM - 0.1 nM) and high (1 microM) concentrations of GTN seemed to be mediated by cyclic GMP. We found a 2-3-fold increase in cGMP at 0.01 - 0.1 nM GTN and a 5-fold increase at 1 microM GTN. Cyclic AMP levels were unchanged. We also found that GTN-induced relaxation was increased, for a given GTN concentration, when the endothelium was removed, especially in the low concentration range.
Ahlner
J
J
Department of Clinical Pharmacology, University Hospital, Linköping, Sweden.
Axelsson
K L
KL
Ljusegren
M E
ME
Grundström
N
N
Andersson
R G
RG
D000818:Animals; D002417:Cattle; D000242:Cyclic AMP / Q000502:physiology*; D006152:Cyclic GMP / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D005996:Nitroglycerin / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
D000242:Cyclic AMP; D005996:Nitroglycerin; D006152:Cyclic GMP