大鼠脑胆碱能系统对血量扩张引起利尿与尿钠排泄的作用

ROLE OF BRAIN CHOLINERGIC SYSTEM ON DIURESIS AND NATRIURESIS INDUCED BY VOLUME EXPANSION IN RATS

本工作在清醒大鼠侧脑室注射胆碱能药物,观察脑胆碱能系统对血量扩张引起利尿与尿钠排泄的作用。侧脑室注射人工脑脊液后进行血量扩张引起尿流量、排钠量和排钾量显著增加(P<0.01)。侧脑室注射胆碱能 M 受体阻断剂阿托品后,血量扩张引起尿流量、排钠量和排钾量增加的效应比注射人工脑脊液组的均显著减弱(P<0.01);而侧脑室注射胆碱能 N 受体阻断剂六烃季胺后,血量扩张引起尿流量、排钠量和排钾量增加的效应与注射人工脑脊液组的相比无显著差异(P>0.05)。侧脑室注射人工脑脊液或阿托品大鼠的肾小球滤过率(GFR)与肾血浆流量(RPF)在血量扩张后均无显著变化(P>0.05)。上述结果表明:大鼠脑胆碱能M 受体参与血量扩张引起利尿与尿钠排泄反应的调节。脑 M 受体的这种作用不是通过改变GFR 和 RPF,而可能是通过未明神经液递机制直接影响肾小管对水钠的重吸收。

The role of brain cholinergic system on diuresis and natriuresis induced byvolume expansion was studied in conscious rats.In a series of experiments,thediuretic,natriuretic and kaliuretic responses induced by volume expansion werecompared in three groups of conscious rats pretreated respectively with intra-cerebroventricular(icv)injection of artificial cerebrospinal fluid(ACSF),atro-pine and hexamethonium.The natriuretic,kaliuretic and diuretic responsesinduced by volume expansion were much less in the animals with icv injectionof atropine than in the control group with injection of ACSF(P<0.01).Whilethe group pretreated with icv injection of hexamethonium showed no significantdecrease in these responses of volume expansion than that of the control(P>0.05).Volume expansion produced no change in insulin and PAH clearance in boththe atropine and the ACSF group.Thus the atropine suppressed diuresis,na-triuresis and kaliuresis are independent of changes in GFR and RPF.It is in-ferred from the results of the present investigation that volume expansion induceddiuresis and natriuresis appear to be due to inhibition of water and sodium re-absorption in the renal tubules and regulated by certain brain cholinergic system.