Hong K W, Rhim B Y, Kim C D, Yoo S E
Department of Pharmacology, College of Medicine, Pusan National University, Korea.
Arch Int Pharmacodyn Ther. 1994 Jul-Aug;328(1):54-66.
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.
在本研究中，评估了克罗卡林对犬和大鼠肠系膜动脉条带张力及⁸⁶Rb⁺外流速率的影响，并与两种动物ATP耗竭动脉条带的相关变量进行了比较。在犬和大鼠肠系膜动脉中，格列本脲均可竞争性拮抗克罗卡林诱导的舒张，且pA₂值相似。当在去氧肾上腺素收缩前或收缩过程中应用克罗卡林时，格列本脲可增强两种动物肠系膜动脉的预收缩或逆转克罗卡林诱导的抑制作用。应用克罗卡林（10 μM）后，两种动物肠系膜动脉的⁸⁶Rb⁺外流速率均显著增加。然而，在ATP耗竭的肠系膜动脉（通过高效液相色谱法验证）中，大鼠出现了⁸⁶Rb⁺外流增加和格列本脲诱导的收缩增强，而犬未出现。综上所述，在犬和大鼠肠系膜动脉条带中，2-脱氧葡萄糖加寡霉素导致的ATP耗竭对ATP敏感性钾通道的激活有不同影响，但对克罗卡林无此影响。
