Dilger James P
Department of Anesthesiology, Stony Brook University, Stony Brook, New York 11794-8480, USA.
Curr Opin Anaesthesiol. 2006 Aug;19(4):390-6. doi: 10.1097/01.aco.0000236138.31099.fc.
The concept of minimum alveolar concentration is central to the study of inhalational anesthetics. The minimum alveolar concentration curve is a population concentration-response curve that describes the relationship between anesthetic concentration and oblation of the movement response to painful stimuli. Two features of the minimum alveolar concentration curve, the anesthetic concentration that immobilizes 50% of patients and the steep slope of the curve, may contain useful mechanistic information. There is some dispute, however, about the interpretation of this information. This review examines hypotheses about the shape of the minimum alveolar concentration curve, and recent theoretical and experimental approaches to the question.
The major determining factor for the slope of a quantal, population concentration-response curve is individual variability. The slope of the underlying in-vitro concentration-response curves contributes as well. At the molecular level, in-vitro curves are not steep. The integration of molecular signals that occurs in cells and neuronal circuits can result in steep in-vitro curves, due to multiple molecular targets, amplification and co-operativity.
The shape of the minimum alveolar concentration curve has not provided any unambiguous clues about the sites or mechanisms of general anesthesia; however, the universality of anesthetic-induced immobility suggests some future research directions.
最低肺泡浓度的概念是吸入麻醉药研究的核心。最低肺泡浓度曲线是一条群体浓度-反应曲线，描述了麻醉药浓度与对疼痛刺激的运动反应消失之间的关系。最低肺泡浓度曲线的两个特征，即使50%患者产生制动作用的麻醉药浓度以及曲线的陡峭斜率，可能包含有用的机制信息。然而，对于这些信息的解读存在一些争议。本综述探讨了关于最低肺泡浓度曲线形状的假说，以及针对该问题的近期理论和实验方法。
定量群体浓度-反应曲线斜率的主要决定因素是个体变异性。潜在的体外浓度-反应曲线的斜率也有影响。在分子水平上，体外曲线并不陡峭。由于多个分子靶点、放大作用和协同作用，细胞和神经回路中发生的分子信号整合可导致体外曲线变陡。
最低肺泡浓度曲线的形状尚未为全身麻醉的位点或机制提供任何明确线索；然而，麻醉诱导制动作用的普遍性提示了一些未来的研究方向。
