Approach to reaction mechanism of general anesthetics by biological and physicochemical methods from new viewpoint

L))我们研究了挥发性麻醉药、苯二氮卓类、氯胺酮和氟哌利多对Na~+，K~+-ATPase活性的影响：(1)除芬太尼外，其他麻醉药均以剂量依赖方式抑制Na，K~+-ATPase活性及其部分反应。不同种类麻醉药对Na，K-ATPase活性的IC50值及其部分反应有一定的规律。麻醉药对磷中间体(EP)形成的影响因麻醉药不同而异。苯二氮卓类药物抑制EP的形成，而异氟醚和氯胺酮则不抑制。氯胺酮可增加EP对钾的敏感性，异氟醚则可降低EP对钾的敏感性。这些结果表明，不同种类的麻醉药对Na，K-ATPase活性的抑制机制不同。(2)苯二氮卓类药物通过抑制EP形成后的步骤抑制Na，K-ATPase活性，这种抑制作用是部分可逆的，而且Na，K-ATPase与苯二氮卓类药物的结合部位不同于GABAA受体。2)为了更好地了解挥发性麻醉药对蛋白质的影响，我们研究了挥发性麻醉剂对Na~(++)，K~(++)-ATPase和ALP的影响。结果表明，挥发性麻醉药的作用并不总是需要脂质的，其作用受同工酶的细微差别，如一级结构的影响，以及由十二烷基硫酸钠引起的轻微的亚基-亚单位相互作用的改变或表面结构的改变。

l) We studied the effects of volatile anesthetics, benzodiazepines, ketamine and droperidol on Na^+, K^+-ATPase activity; (1) All of anesthetics except fentanyl inhibited Na, K-ATPase activity and its partial reactions in a dose dependent manner. There were certain patterns, characteristic of each category of the anesthetics, in the order of IC50 values of Na, K-ATPase activity and its partial reactions. Effects of the anesthetics on the phosphointermediate (EP) formation differed among the anesthetics. Benzodiazepine inhibited the EP formation, whereas isoflurane and ketamine did not. The sensitivity of EP to potassium was increased by ketamine but was decreased by isoflurane. These findings suggest that the inhibitory mechanisms of general anesthetics against Na, K-ATPase activity are diverse among the categories of anesthetics. (2) Benzodiazepines inhibited Na, K-ATPase activity by inhibiting the step after EP formation and the inhibition was partialy reversible, and that binding sites of Na, K-ATPase for benzodiazepines were different from those of GABAA receptor.(3)Droperidoi inhibited the ATPase activity of Na, K-ATPase by decreasing the rate of dephosphorylation of EP and that the inhibition was reversible. 2) To better understand the effects of volatile anesthetics on proteins, we studied the effects of volatile anesthetics on Na^+, K^+-ATPase that requires lipids for activity and alkaline phosphatase (ALP) that does not require lipids for activity. The results suggested that lipid is not always necessary for the action of volatile anesthetics, and that the action of volatile anesthetics is influenced by the slight difference of isozymes, for example, primary structure and by the change of slight subunit -subunit interaction or alteration of surface structure caused by SDS.