Relaxant effects of cromakalim and ATP depletion in dog and rat mesenteric arteries--species differences.
In the present study, the effects of cromakalim on tension and 86Rb+ efflux rate were evaluated in strips of dog and rat mesenteric arteries and compared with the variables obtained from ATP-depleted strips of both species. The cromakalim-induced relaxation was competitively antagonized by glibenclamide, with similar pA2 values, in both dog and rat mesenteric arteries. Glibenclamide caused an enhancement of the precontraction or a reversal of the cromakalim-induced inhibition in the mesenteric arteries of both species when cromakalim was applied prior to or during phenylephrine-contraction. The 86Rb+ efflux rate from the mesenteric arteries was significantly increased in both species after application of cromakalin (10 microM). However, in the ATP-depleted mesenteric artery (verified by high performance liquid chromatography), an increase in 86Rb+ efflux and a glibenclamide-induced enhancement of contraction were observed in the rat, but not in the dog. Taken together, between dog and rat mesenteric arterial strips, a differential effect of ATP depletion with 2-deoxyglucose plus oligomycin was identified in the activation of ATP-sensitive K+ channels, but not of cromakalim.
Hong
K W
KW
Department of Pharmacology, College of Medicine, Pusan National University, Korea.
Rhim
B Y
BY
Kim
C D
CD
Yoo
S E
SE
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D019806:Cromakalim; D003847:Deoxyglucose / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009840:Oligomycins / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010865:Pilot Projects; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012413:Rubidium / Q000378:metabolism; D013045:Species Specificity; D014665:Vasodilator Agents / Q000378:metabolism / Q000494:pharmacology*
D001578:Benzopyrans; D009840:Oligomycins; D015221:Potassium Channels; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; D010656:Phenylephrine; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D012413:Rubidium; D005905:Glyburide