Objective: The aim of the present study was to evaluate the diuretic effect and explore its mechanism of Ainsliaea grossedentata in water-loaded rats. Method: The rats were divided and given extractive of A.grossedentata at three different dose(2.5

10

20 g·kg-1)

and given furosemide(10 mg·kg-1) as positive control group. After the first administration

the urine of rats was collected at 1

2

4

6

24 h to study the effect of urine output and electrolyte concentration (Na+

K+ and Cl-) and regulation of the relative mRNA expression of aquaporin-1 (AQP1)

aquaporin-2 (AQP2) and aquaporin-3 (AQP3) in water-loaded rats. Result: Compared with normal group

after single dose of the extract of A. grossedentata

urine output was significantly increased

which began at 4 h after the treatment. The extract increased urinary levels of Na+

K+

and Cl- at 24 h markedly. After administration of 8 days

the extract significantly reduced expression of AQP2 and lower expression of AQP3 to some extent

but there was no significant difference in the expression of AQP1. Conclusion: A. grossedentata has conspicuous diuretic activity

the possible mechanisms may restrain the relative mRNA expression of AQP1 and AQP2 as well as renal tubular reabsorption function.