Jochem J
Department of Physiology, Silesian Medical University, Zabrze, Poland.
J Physiol Pharmacol. 2002 Mar;53(1):75-84.
Volume-controlled irreversible haemorrhagic shock in rats produced by blood withdrawal until stabilisation of critical mean arterial pressure (MAP) 20-25 mmHg is associated with an extreme decrease in cardiac index (CI) and an increase in total peripheral resistance index (TPRI), with reductions in renal (RBF), hindquarters (HBF) and mesenteric blood flow (MBF), and leads to the death of all control animals within 30 min. Histamine (100 nmol) injected intracerebroventricularly (i.c.v.) in the early phase of critical hypotension produces a prompt and long-lasting increase in MAP and heart rate, with a 100% survival for 2 h after treatment. The effects are associated with the rise in the circulating blood volume and CI, and the decrease in TPRI, with the increase in RBF and HBF, and persistently lowered MBF. Both splenectomy and ligation of the suprahepatic veins inhibit histamine-induced increase in circulating blood volume as well as cardiac and regional haemodynamic effects. It can be concluded that histamine administered icv activates central endogenous compensatory mechanisms, which leads to the reversal of haemorrhagic shock conditions due to the mobilisation of blood from venous reservoirs, the increase in circulating blood volume and its redistribution. Moreover, histamine evokes the rises in Cl and perfusion of the renal and skeletal muscle vascular regions.
通过放血使大鼠产生容量控制的不可逆失血性休克，直至临界平均动脉压（MAP）稳定在20 - 25 mmHg，这与心脏指数（CI）极度降低、总外周阻力指数（TPRI）升高、肾血流量（RBF）、后肢血流量（HBF）和肠系膜血流量（MBF）减少相关，并导致所有对照动物在30分钟内死亡。在临界低血压早期经脑室内（i.c.v.）注射组胺（100 nmol）可使MAP和心率迅速且持久升高，治疗后2小时存活率达100%。这些效应与循环血容量和CI升高、TPRI降低、RBF和HBF增加以及MBF持续降低有关。脾切除术和肝上静脉结扎均抑制组胺诱导的循环血容量增加以及心脏和局部血流动力学效应。可以得出结论，经脑室内给予组胺可激活中枢内源性代偿机制，这由于从静脉储血库动员血液、循环血容量增加及其重新分布而导致失血性休克状况的逆转。此外，组胺引起CI升高以及肾和骨骼肌血管区域灌注增加。
