Borders J L, Granger H J
Hypertension. 1986 Mar;8(3):184-91. doi: 10.1161/01.hyp.8.3.184.
Peripheral resistance was examined in the microcirculation of the rat cremaster muscle using a network-conserved parameter, power dissipation. Previous studies of peripheral resistance used network-sensitive parameters, and their interpretation is limited by tacit assumptions about the structure of the peripheral vasculature. Power dissipation is directly linked to the resistive process, providing a measure of resistance based on the actual hemodynamics of the network. The dissipation parameter was quantified with the usual vascular parameters of velocity and vessel segment length; 991 segment lengths were measured in 12 normotensive Wistar-Kyoto rats and 16 spontaneously hypertensive rats. Arterial power dissipation was significantly elevated over a wide range of vessel segments; blood flow ranged from 0.08 to 80 nl/sec. Since the largest vessels showed the greatest power dissipation, the organ resistance elevation seen in hypertension in the cremaster apparently is mediated by the larger vessels in the high flow range. Vessel segment length and number of dissipative vessels were unchanged. The increase in power dissipation was due to a network-averaged reduction in mean vessel diameter. Power dissipation also increased significantly in the fastest flowing venous microvessels (greater than 25 nl/sec), also due to a reduction in vessel segment diameter.
使用一个网络守恒参数——功率耗散，在大鼠提睾肌的微循环中检测外周阻力。以往关于外周阻力的研究使用的是对网络敏感的参数，并且它们的解释受到对外周血管系统结构的默认假设的限制。功率耗散与电阻过程直接相关，基于网络的实际血流动力学提供了一种阻力测量方法。用通常的血管参数速度和血管段长度对耗散参数进行量化；在12只正常血压的Wistar-Kyoto大鼠和16只自发性高血压大鼠中测量了991个血管段长度。在很宽的血管段范围内，动脉功率耗散显著升高；血流范围为0.08至80 nl/秒。由于最大的血管显示出最大的功率耗散，提睾肌高血压中所见的器官阻力升高显然是由高血流范围内的较大血管介导的。血管段长度和耗散血管数量未改变。功率耗散的增加是由于平均血管直径的网络平均减小。在流速最快的静脉微血管（大于25 nl/秒）中，功率耗散也显著增加，这也是由于血管段直径减小所致。
