高张 NaCl 溶液对失血大鼠血压代偿的作用

EFFECT OF HYPERTONIC NaCl SOLUTION ON ARTERIAL PRESSURE COMPENSATION AFTER HEMORRHAGE IN RATS

使麻醉大鼠在5min 内失血,致使动脉血压下降至25mmHg,然后静脉注射1/10失血量的高张 NaCl 溶液(Hypertonic solution,HS,7.5%NaCl)或生理盐水(NS)。静脉注射少量 HS 能明显促进失血后血压回升,这个作用能为6-羟多巴胺或巯甲丙脯酸显著减弱,若将这两个药物同时应用,则 HS 的升压作用完全被解除。HS 使血浆 Na^+浓度明显升高,而 NS使之下降。侧脑室微量注射 HS 后也明显促进动脉血压的恢复。这些实验结果表明失血后静脉注射少量 HS 可升高血浆 Na^+浓度,高 Na^+作用于中枢神经系统,激活交感神经系统和肾素-血管紧张素系统,从而促使血压迅速恢复。

Rats were bled within 5 min in lowering mean arterial pressure(MAP)to25 mmHg and were subsequently infused intravenously with hypertonic(7.5%NaCl)or normal saline m a volume equal to 10% of the amount of the lost blood.Intravenous infusion of hypertonic saline significantly facilitated posthemor-rhagic recovery of MAP,which was markedly attenuated by 6-hydroxydopamineor Captopril When these two drugs were used together,the attenuation effectwas complete.While hypertonic saline significantly increased plasma Na^+ con-centration,normal saline only gave rise to a decrease.Intracerebroventricularinjection of hypertonic NaCl solution also facilitated the recovery of MAP signi-ficantly.These results suggest that after hemorrhage increased plasma Na^+concentration following i.v.of a small amount of hypertonic saline may act on thecentral nervous system and activate sympathetic nervous system and renin angio-tensin system to facilitate a rapid recovery of MAP.