Objective 　To establish a new practical method to assess the cerebral blood flow autoregulation. Methods　We assessed the flow velociey of middle cerebral artery with transcranial Doppler and recorded invasively the blood presure simultaneonsly. Then on the basis of critical closing pressure (CCP), the lower limit of cerebral blood flow autoregulation and the blood flow resistance of arterioles were calculated.The data compared with the results generated by routine method. Results　The lower limit of autoregulation working out by CCP was 70.88±24.05 mmHg, which was similar to the result measured by routine method. The lower limit of autoregulation and the arteriole resistance in RHR were significantly higher than those of normal controls, and highly relate to arterial blood pressure significantly, especially pulse pressure. Conclusions　The physiology and pathology of cerebral blood flow can be evaluated conveniently and accurately by assessment of the lower limit of autoregulation and arterioles resistance with CCP.

AIM:To study the effect of hypertensive arteriosclerosis on cerebral blood flow autoregulation (CBFA), and to introduce a new method to measure the lower limit. METHODS:The blood velocities and blood pressure was recorded simultaneously and the curves of CBFA were analyzed and classified into classical and non-classical pattern. The lower limit were determined by clinical closing pressure (CCP) and the curve CBFA. RESULTS:When the blood pressure was decreasing, the classical and non-classical pattern of the cerebral blood flow autoregulation were 25% and 75% respectively in normal SD rats, while they were 40.55% and 54.45% respectively in renovascular hypertensive rats (RHR). However, when the blood pressure was elevating, the classical and non-classical pattern were 76.47% and 23.53% respectively in SD rats, while they were all classical in RHR. Furthermore, in SD and RHR ras, the lower limits measured by CCP were well in accordance with that measured by CBFA. CONCLUSION:Hypertensive arteriosclerosis could influence the limits and the patterns of cerebral blood flow autoregulation. The lower limit of CBFA can be measured and analyzed by CCP.

AIM: To study the effect of hypertensive arteriosclerosis on cerebral blood flow autoregulation (CBFA), and to introduce a new method to measure the lower limit. METHODS: The blood velocities and blood pressure was recorded simultaneously and the curves of CBFA were analyzed and classified into classical and non-classical pattern. The lower limit were determined by clinical closing pressure (CCP) and the curve CBFA. RESULTS: When the blood pressure was decreasing, the classical and non-classical pattern of the cerebral blood flow autoregulation were 25% and 75% respectively in normal SD rats, while they were 40.55% and 54.45% respectively in renovascular hypertensive rats (RHR). However, when the blood pressure was elevating, the classical and non-classical pattern were 76.47% and 23.53% respectively in SD rats, while they were all classical in RHR. Furthermore, in SD and RHR ras, the lower limits measured by CCP were well in accordance with that measured by CBFA. CONCLUSION: Hypertensive arteriosclerosis could influence the limits and the patterns of cerebral blood flow autoregulation. The lower limit of CBFA can be measured and analyzed by CCP.

Purpose To summarized the methods for establishment, characteristics of vascular lesions in brain and heart and the application of stroke-prone renovascular hypertensive rats (RHRSP).Data sources and methods Most published original articles about RHRSP in our laboratory were reviewed.Results After the renal arteries were constricted bilaterally with ring-shape silver clips, the stroke-prone renovascular hypertensive rats were established. Hypertension was produced in all RHRSP (100%). The peak of blood pressure in RHRSP reached 29.1±3.0 kPa. The lesions of cerebral arteries and arterioles and the damage of cerebral capillary structure by hypertension were observed in the RHRSP. The incidence of spontaneous stroke was 56.4% within 40 weeks after the renal artery constriction. Left ventricular hypertrophy and small coronary arterial lesions in myocardium were discovered in all RHRSP. Myocardial infarction occurred spontaneously in 41.8% of RHRSP. The animal models have been used for the studies on mechanisms of stroke and myocardial infarction.Conclusions Because the vascular lesions in cerebrum and heart in RHRSP are similar to that in human beings with hypertension, RHRSP can be used in the studies on mechanisms of hypertensive arteriosclerotic stroke and cardiac lesions and on verifying the effects of different medications to complications of hypertension, and the results might be more reliable than that in animal models without hypertension.