Objective To study the mechanism of stroke in hyper te nsive rats induced by cold pathogens.Methods Totally 100 SD rats were ra ndomized into normal group（n=30）

model group（n=40） and sham operation group（ n=30）.Reno vascular hypertension model was established by clipping two sides of renal arter y.Stroke was induced by simulating a sudden drop in temperature.Ten rats were randomly selected before

during and after drop in temperature respectively in e a ch group.The level of endothelin-1（ET-1）

angiotensinⅡ（AngⅡ）

arginine va so pressin（AVP） and NO was detected in each group before and after sudden drop in temperature.Results After the sudden drop in temperatu re

13 rats suffered cere bral hemorrhage in 20 rats of the model group

among which 3 died.Stroke did no t attack in other groups.The levels of AngⅡ and AVP were increased in t he normal group

but the level of NO were significantly decreased（P<0.05）. The levels of ET-1

AngⅡ and AVP were significantly increased in the model gr oup（ P<0.05）

and the level of NO was increased as well.The levels of NO

Ang Ⅱ

AVP and NO were increased in the model rats

while the level of ET-1 was significantly d ecreased as compared with that of the normal group at the same time（P<0.0 5）.Con clusion The mechanism of stroke in hypertensive rats induced by cold pa thogens is due to disorder of angiokinesis.