brain . The investigation might help to further study the physiological significance of " peripheral-type" benzodiazepines receptor.

ObjectiveTo observe the effect of portal blood flow on rat's liver with prehepatic portal hypertension.MethodsSixty-six male Wistar rats were randomly divided into five groups:partial portal vein transfixation group( A,n =20),hepatic artery transfixation after partial portal veins transfixation group( B,n =20),hepatic artery transfixation group (C,n =10),SO group( D,n =10 ),hepatic artery and partial portal vein transfixation group ( E,n =6 ).The mortality as well as the biochemical examination wereobserved at the 12th week after operation.Then the density of the microvascular in portal area and proliferating cell nuclear antigen expression of intro-hepatic bile duct epithelium were determined by immunohistochemical staining method.The ultra microstructure changes of hepatocytes were observed under transmission electron microscope.Results Biochemical examination,including glutamic-oxa-lacetic transaminase,glutamic-pyruvic transaminase and total protein,showed no significant differences anong all groups (P ＞0.05) at the 12th week after operation.Glutamie-oxalacetic transaminase in group A,in group B,in group C and in group D are (132.69±21.03) U/L,(154.40±28.73) U/L,(125.84±26.60) U/L,(134.02±18.42) U/L; glutamic- pyruvic transaminase in group A,in group B,in group C and in group Dare (39.33±8.62) U/L,(44.84 t9.47)U/L,(40.41±8.04) U/L,(38.47±7.29) U/L.Compared with groups C and D,the mortality rate (group A 20％ ; group B 25％),and the microvascular number in portal area increased obviously in group B and A(P ＜0.05).The proliferating cell nuclear antigen expressions of intra-hepatic bile duct epithelium increased significantly in group B (mean optical density 0.345±0.027 compared with the rest groups mean optical density in group A,in group C and in group D are 0.264 ± 0.015,0.258±0.022,0.249±0.021 ) ( P ＜ 0.01 ) ; fat accumulation in the hepatocytes and mitochondria vacuolization were observed under transmission electron microscopic in group A and group B.ConclusionsThe portohepatic collateral circulation still has its significance in liver blood supply of prehepatio portal hypertensive rat; the epithelium of intra-hepatic bile duct was mildly damaged and the microvascular number in hepatic portal area increased as well as the fat accumulated in hepatocytes of prehepatic portal hypertensive rat; if the hepatic artery blood supply is lost,these changes would become more obviously.

The mode of action of V-type organophosphate poisons on acetylcholinesterase has been studied. It shows that the leaving group of V-type poisons is dialkylamino-ethyl-thio radical,and the phosphonyla-ting site on the enzyme molecule is similar to that of the G-type poison soman, as shown by the competition experiments.