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

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。

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

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.