Relationship between vasoconstriction and histamine induced vasodilation.
Histamine produced significantly greater vasodilation in rabbit ear arteries constricted by noradrenaline than when the same arteries were constricted by either caffeine or barium. Histamine dilation in the presence of caffeine was also significantly greater than that in the presence of barium. These results suggest that histamine may produce vasodilation through at least two different modifications of intracellular calcium mobilisation.
D000818:Animals; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism; D001464:Barium / Q000037:antagonists & inhibitors; D002110:Caffeine / Q000037:antagonists & inhibitors; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004431:Ear, External / Q000098:blood supply; D006632:Histamine / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000378:metabolism; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D011817:Rabbits; D014666:Vasomotor System / Q000187:drug effects*
D001464:Barium; D002110:Caffeine; D006632:Histamine; D002118:Calcium; D009638:Norepinephrine