Cellular mechanisms of the steroid-induced vascular responses in the rabbit ear artery.
1. In anesthetized rabbits, topical application of dexamethasone to the ear produced an initial vasodilation followed by a vasoconstriction with long delay (120 min). Diphenhydramine inhibited the former, but not the latter. 2. In isolated rabbit ear arteries, dexamethasone reduced the amplitude of contractions of smooth muscles produced by nerve stimulation, noradrenaline and high-K solution, only at high concentrations (> 10(-5) M). 3. The initial vasodilation induced by topical application of dexamethasone may be related to endogenous histamine, while the delayed constriction response may not be direct actions of steroid to smooth muscles.
Miyahara
H
H
Department of Dermatology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Imayama
S
S
Hori
Y
Y
Suzuki
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D003907:Dexamethasone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004155:Diphenhydramine / Q000494:pharmacology; D004431:Ear, External / Q000098:blood supply*; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013256:Steroids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects
D013256:Steroids; D009569:Nitric Oxide; D003907:Dexamethasone; D004155:Diphenhydramine; D000109:Acetylcholine; D011188:Potassium; D009638:Norepinephrine