急性代谢性酸中毒时CSFpCO_2在CSF酸碱调节中的作用  

Role of CSF pCO_ 2 in CSF acid-base regulation in acute metabolic acidosis

作　　者：金发光[1] 钱桂生[1] 毛宝龄[1] 郭生健 赵自强[1] 黄桂君[1] 

机构地区：[1]第三军医大学新桥医院全军呼吸专科中心

出　　处：《中国病理生理杂志》1995年第3期281-285,共5页Chinese Journal of Pathophysiology

摘　　要：本文旨在探讨急性代酸时ＣＳＦｐＣＯ＿２在ＣＳＦ酸碱调节中的作用及其机制。４组急性代酸犬模型均由静脉内输入０．２ＮＨＣｌ产生，血浆［ＨＣＯ＿３－］ｌｈ内下降到１２±２ｍｍｏｌ／Ｌ，实验持续６ｈ。Ⅰ组控制ＰａＣＯ＿２常，６ｈ时ＣＳＦ［ＨＣＯ＿３－］下降了１．１ｍｍｏｌ／Ｌ；Ⅱ组自然呼吸，ＣＳＦｐＣＯ＿２伴随ＰａＣＯ＿２下降，６ｈ时ＣＳＦ［ＨＣＯ＿３－］下降了６．５ｍｍｏｌ／Ｌ；Ⅲ组机械通气，ＰａＣＯ＿２和ＣＳＦｐＣＯ２均迅速下降，６ｈ时ＣＳＦ［ＨＣＯ＿３－］下降了８．２ｍｍｏｌ／Ｌ；Ⅳ组控制ＰａＣＯ＿２正常，脑室注入乙酰唑胺，６ｈ时ＣＳＦ［ＨＣＯ＿３－］下降了１１．４ｍｍｏｌ／Ｌ。结果说明急性代酸时．ＣＳＦ［ＨＣＯ＿３－］取决于ＣＳＦｐＣＯ＿２。ＣＳＦＨＣＯ＿３－主要来源于ＣＮＳＣＯ＿２的水化作用，与ＣＡ活性显著相关。The role of pCO_2 in cerebrospinal fluid(CSF)acid-base regulation inacute metabolic acidosis was studied. Acute metabolic acidosis was induced by the intra-venous infusion of 0.2N HCl in four groups of anesthetized dogs(n=5)fOr six hourswhen PaCO_2 was changed at different rates. Plasma[HCO_3-]was lowered to 12 ± 2mmol/Lwithin one hour and maintained at that level thereafter in all groups.(1) In groupIPaCO_2 were kept normal while metabolic acidosis was induced.The CSF[HCO_3-]fell by only 1. 1mmol/L after sixhours and was not significantly different from control.(2)Group Ⅱdogs breathed spontaneously while metabolic acidosis was induced. There wasa gradual drop in PaCO_2 accompanied by a similar drop in CSF pCO_2 CSF[HCO_3-]fell significanly by 6.5mmol/L at 6 hours and was parallel with the fall in CSF pCO_2.(3)In order to show interdependence of the rate of fall in CSF[HCO_3-]with rate of fall inCSF pCO_2 five dogs were hyperventilated mechanically and PaCO_2 reduced rapidly andmaintained there for six hours .CSF pCO_2 followed PaCO_2 CSF bicarbonate fell rapidlyand droped 8.2mmol/L.In group Ⅱ and group Ⅲ the fall in CSF[HCO_3-]paralleledthe drop in pCO_2-.(4)Group Ⅳ PaCO_2 were kept normal while metabolic acidosis wasinduced, but ventricles of brain was injected actazolamide. The CSF[HCO_3-]droped1.4mmol/L after six hours. It suggested that the CSF[HCO_3-]is dependent upon CSFpCO_2,and the formation of HCO_3 in CSF is closely related to pCO-2 and the activityof carbonic anhydrase.CSF HCO-3- come from effects of CO_2 hydroxylation.

关 键 词：脑脊液 酸碱平衡 脉络丛 碳酸酐酶类 酸中毒 

分 类 号：R589.602[医药卫生—内分泌] R363.13[医药卫生—内科学]