Ledingham J M
Medical Unit, London Hospital Medical College, UK.
J Hypertens Suppl. 1989 Sep;7(4):S97-104; discussion S105.
The hypothesis examined here is that autoregulation of peripheral flow is the dominant factor in initiating and maintaining the rise in peripheral resistance in hypertension. Vascular smooth muscle possesses myogenic activity, which is dependent upon wall tension and thus upon intravascular pressure, but the activity is modulated by metabolic factors which are flow-dependent. Autoregulation of flow by the microvessels is considered to be a reflection of the wider concept of autoregulation of tissue or cellular oxygen tension through the control of oxygen delivery and extraction in relation to oxygen consumption. Indirect evidence for the hypothesis, involving the measurement of oxygen delivery and consumption both in the whole body and in defined regions in various forms of hypertension, is discussed. Individual and species differences in the type of response of the microvessels to changes in oxygen tension and in the dependence/independence of oxygen consumption on flow may account for some of the discrepant observations. Specific criticisms of the hypothesis are discussed and it is concluded that the balance of indirect evidence supports the hypothesis. Lastly, if autoregulation is indeed involved in development of hypertension, it constitutes only a part of a complex pathogenic mechanism, whose major role is to maintain sodium and water balance in the body.
本文检验的假设是，外周血流的自动调节是高血压患者外周阻力升高起始及维持过程中的主要因素。血管平滑肌具有肌源性活动，其依赖于管壁张力，进而依赖于血管内压力，但该活动受代谢因素调节，而代谢因素又依赖于血流。微血管对血流的自动调节被认为是通过控制与氧消耗相关的氧输送和摄取，对组织或细胞氧张力自动调节这一更广泛概念的一种体现。文中讨论了该假设的间接证据，包括在各种类型高血压患者的全身及特定区域测量氧输送和消耗。微血管对氧张力变化的反应类型以及氧消耗对血流的依赖性/非依赖性方面的个体和物种差异，可能解释了一些相互矛盾的观察结果。文中讨论了对该假设的具体批评意见，并得出结论：间接证据的平衡支持该假设。最后，如果自动调节确实参与了高血压的发生发展，那么它只是复杂致病机制的一部分，其主要作用是维持体内钠和水平衡。
