title: Heterogeneous effects of Ca2+ entry blockers on biphasic constriction of the rabbit ear artery.
abstract: In the rabbit ear artery, nifedipine, verapamil, diltiazem and bepridil were found to be more potent in inhibiting the tonic than the phasic response to norepinephrine, while KB-944 and W-7 blocked these two responses equally. Since in the ear artery norepinephrine utilizes intracellular and extracellular Ca2+ for its phasic and tonic responses, respectively, the non-selective inhibitory effect of KB-944 suggests that Ca2+ entry blockade may not account solely for its vasodilator effect.
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004423:Ear / Q000098:blood supply; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D002121:Calcium Channel Blockers; D009638:Norepinephrine