Organ Specificity in the responses of isolated arteries to anesthetics.

本研究试图阐明不同器官(脑动脉、冠状动脉、肠系膜动脉、肾动脉和股动脉)对麻醉剂反应的器官特异性。(1)在静息张力下的动脉条上，加入硫代戊醛和硫喷妥钠(10^&lt；-5&gt；M)可引起剂量相关的收缩，大脑动脉的收缩明显强于脑外动脉。舒巴比妥和戊巴比妥没有产生明显的收缩。硫代巴比妥酸盐引起的收缩可被钙通道阻滞剂减弱，并可被细胞外液中钙离子的清除所消除。(2)在先前用Kc1或前列腺素F_2α(PGF_&lt；&gt；α)收缩的动脉条上，低浓度硫代巴比妥酸盐(&lt；10；&lt；-4&gt；M)引起进一步的收缩，而在高浓度(&gt；3x10；&lt；-4&gt；M)则产生深刻的松弛，表明硫代巴比妥酸盐具有双相效应。与之相反，羟巴比妥酸盐仅具有松弛作用。(3)研究了大(&gt；2.0 mm，OD)和小(&lt；1.0 mm，OD)氟烷和异氟醚对氟烷和异氟醚反应的地区差异。氟烷(1-3MAC)和硝酸甘油(NTG)对大冠状动脉的松弛作用大于对小冠状动脉的松弛，而异氟烷(1-3MAC)和腺苷(10-3MAC)和腺苷(10-3MAC；-7)对大冠状动脉的松弛作用在不同器官的血管效应是一致的。这些不同的影响可能导致麻醉过程中血流的不均匀。

The present study attempts to clarify the organ specificity in the responses to anesthetics of isolated arteries of different organs (cerebral, coronary, mesenteric, renal and femoral arteries). (1) In arterial strips under resting tension, the addition of thiamylal and thiopental(10^<-5> to 10^<-3> M) caused a dose-related contraction; the contraction was significantly more intense in cerebral than in extracerebral arteries. Secobarbital and pentobarbital failed to produce a significant contraction. Thiobarbiturates-induced contraction was attenuated by Ca channel blockers and abolished by the removal of Ca^<++> from extracellular fluids.(2) In arterial strips previously contracted with KC1 or prostaglandin F_2alpha (PGF_<>alpha), thiobarbiturates in low concentrations (<10^<-4> M) produced a further contraction and in high concentrations (>3x10^<-4> M) a profound relaxation, indicating that thiobarbiturates possess biphasic effects. By contrast, oxybarbiturates were revealed to possess only relaxing effect.(3) Regional difference of the response to halothane and isoflurane of large (>2.0 mm, OD) and small (<1.0 mm, OD) was investigated. Halothane (1-3 MAC) and nitroglycerin (NTG, 10^<-9> to 10^<-5> m) were revealed to produce greater relaxations in large than in small coronary arteries, and in contrast, isoflxirane (1-3 MAC) and adenosine (10^<-7> to 10^<-4> m) was revealed to produce relaxations greater in small than in large coronary arteries.These findings with isolated arteries from different organ suggest that the vascular effects of anethetics are uniform in different organs. These different effects may contribute to maldistribution of blood flow during anesthesia.