title: Endothelium-dependent effects of carteolol.
abstract: Experiments were designed to study the effect of the beta adrenergic antagonist, carteolol, on the endothelium-dependent responsiveness of isolated arteries. Rings of canine coronary arteries were suspended in organ chambers for isometric tension recording; carteolol inhibited the relaxation to isoproterenol and abolished the difference in responsiveness to the beta adrenergic agonist between rings with and without endothelium. Carteolol did not cause endothelium-dependent relaxations of femoral or coronary arteries. In bioassay experiments, carteolol augmented the basal release of relaxing factors from the endothelium of the femoral artery; this effect was prevented by indomethacin. In rings of femoral arteries, carteolol increased the endothelium-dependent relaxations induced by the alpha-2 adrenergic agonist UK 14,304; this was not affected by indomethacin but prevented by propranolol. Carteolol did not modify the endothelium-dependent relaxations to acetylcholine, adenosine diphosphate, bradykinin, thrombin and the Ca+-ionophore A23187. Carteolol inhibited the endothelium-dependent hypoxic contraction of the canine coronary artery. It did not affect endothelium-dependent contractions to acetylcholine in the aorta of the spontaneously hypertensive rat. These experiments suggest that carteolol facilitates the abluminal release of endothelium-dependent relaxing factor caused by alpha-2 adrenergic activation, and causes the intraluminal release of vasodilator prostaglandins. The compound prevents the endothelium-dependent contractions which are not mediated by products of cyclooxygenase. These actions may contribute to the vasodilatator properties of carteolol in the intact organism.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001681:Biological Assay; D002354:Carteolol / Q000494:pharmacology*; D004285:Dogs; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011412:Propanolamines / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011942:Receptors, Adrenergic, alpha; D002354:Carteolol; D007545:Isoproterenol; D000109:Acetylcholine