Fasth S, Hultén L, Nordgren S
Acta Physiol Scand. 1980 Dec;110(4):343-50. doi: 10.1111/j.1748-1716.1980.tb06679.x.
The mutual changes in hepatic and small intestinal blood flow on selective nervous stimulation of the periarterial vasoconstriction fibres, were studied in anaesthetized cats. Occlusion of the hepatic artery did not change portal blood flow, whereas occlusion of superior mesenteric blood flow caused a significant increase in hepatic arterial flow. Stimulation of the hepatic sympathetic nervous supply caused a phasic blood flow response with a marked transient peak flow reduction of hepatic arterial blood flow. The magnitude of the peak response varied with the frequency of the stimulation. Despite continuous stimulation the first phase went over into a second phase of less pronounced vasoconstriction. This "steady state" blood flow, was maintained at about 20% below the control level, irrespective of stimulation frequency. Corresponding in time with the peak vasoconstriction there was a transient increase of portal pressure. Sympathetic nerve stimulation increased portal pressure even on occlusion of the hepatic artery. Stimulation of the mesenteric sympathetic nerves evoked the characteristic transient peak vasoconstrictor response consisting of two phases, a brief intense peak resistance response followed by a second phase of less pronounced but generally well maintained constriction. Simultaneously a slight reduction of portal pressure and hepatic arterial vascular resistance was regularly seen. In contrast to the observations in the hepatic arterial circuit the magnitude of this "steady state" blood flow in the small intestine was dependent on the rate of the stimulation, however. On simultaneous stimulation of the hepatic and mesenteric sympathetic nerves the hemodynamic responses were largely the same as when these nerves were stimulated separately. The portal pressure affecting mean capillary pressure in the intestine differed, however. Small and variable pressure changes were followed by rapid return towards control and during steady state it did not differ from the prestimulatory level.
在麻醉猫身上，研究了对动脉周围血管收缩纤维进行选择性神经刺激时肝血流和小肠血流的相互变化。阻断肝动脉不会改变门静脉血流，而阻断肠系膜上动脉血流会导致肝动脉血流显著增加。刺激肝交感神经供应会引起阶段性血流反应，肝动脉血流出现明显的短暂峰值流量减少。峰值反应的幅度随刺激频率而变化。尽管持续刺激，第一阶段会过渡到血管收缩不太明显的第二阶段。这种“稳态”血流维持在比对照水平低约20%，与刺激频率无关。与峰值血管收缩同时，门静脉压力会短暂升高。即使在阻断肝动脉的情况下，交感神经刺激也会增加门静脉压力。刺激肠系膜交感神经会引发特征性的短暂峰值血管收缩反应，包括两个阶段，先是短暂强烈的峰值阻力反应，随后是血管收缩不太明显但通常维持良好的第二阶段。同时，门静脉压力和肝动脉血管阻力通常会略有降低。然而，与肝动脉循环中的观察结果不同，小肠中这种“稳态”血流的幅度取决于刺激速率。同时刺激肝和肠系膜交感神经时，血流动力学反应与分别刺激这些神经时基本相同。然而，影响小肠平均毛细血管压力的门静脉压力有所不同。压力变化小且多变，随后迅速恢复到对照水平，在稳态时与刺激前水平没有差异。
