Grossman H J, Grossman V L, Bhathal P S
Department of Pathology, University of Melbourne, Victoria, Australia.
Hepatology. 1995 Jan;21(1):162-8.
The relationship between the perfusion pressure (P) and resistance (R) of the intrahepatic portal vascular bed was determined in isolated rat liver preparations perfused with fresh, heparinized rat blood (hematocrit 30%), with rat blood containing a vasodilator agent (sodium nitroprusside, 1 X 10(-3) mol/L), or with 2.5% bovine serum albumin in Krebs-Henseleit buffer (BSA-KH). Pressure-flow curves were constructed over an extended range of portal venous inflow (0 to 70 mL.min-1, corresponding to a flow rate per gram liver wet weight, Q, of approximately 0 to 7 mL.min-1.g-1). Subsequent analysis showed that two mathematical expressions adequately described the data over the full range of flow. Thus, the pressure-flow curve could be represented by (a) the sum of a linear plus a hyperbolic function, i.e., P = Q.R' + Pmax.Q/(Q + Km), where R', Pmax, and Km are constants, or (b) by the simple equation G = C.P, where G is the conductance (Q/P), and C is a conductivity constant. The values of R', Pmax, Km, and C were significantly different under each of the circumstances investigated, but the form of the curve was not altered. Hence, it is proposed that these parameters can be used to describe the fundamental hemodynamic properties of the portal vascular bed of the isolated rat liver. The results are discussed in terms of the microvascular recruitment and distensible resistance vessel models of the hepatic microcirculation.
在离体大鼠肝脏标本中，测定肝内门静脉血管床的灌注压力（P）与阻力（R）之间的关系。这些标本用新鲜的、肝素化的大鼠血液（血细胞比容30%）、含有血管扩张剂（硝普钠，1×10⁻³ mol/L）的大鼠血液或 Krebs-Henseleit 缓冲液中的2.5%牛血清白蛋白（BSA-KH）进行灌注。在门静脉流入量的扩展范围内（0至70 mL·min⁻¹，对应于每克肝脏湿重的流速，Q，约为0至7 mL·min⁻¹·g⁻¹）构建压力-流量曲线。随后的分析表明，两个数学表达式能充分描述整个流量范围内的数据。因此，压力-流量曲线可以由（a）线性函数加双曲线函数之和表示，即P = Q·R'+Pmax·Q/(Q + Km)，其中R'、Pmax和Km为常数，或者（b）由简单方程G = C·P表示，其中G为传导率（Q/P），C为传导常数。在每种研究的情况下，R'、Pmax、Km和C的值均有显著差异，但曲线形式未改变。因此，建议这些参数可用于描述离体大鼠肝脏门静脉血管床的基本血流动力学特性。根据肝微循环的微血管募集和可扩张阻力血管模型对结果进行了讨论。
