Effects Of Propofol On Hemodynamics As Well As And Renal Function In Aged Hypertensive Rats

Objectives: To observe the effects of propofol intravenous anesthesia on hmodynamics and rennin-angiotensin system as well as renal function in aged spontaneously hypertensive rats (SHR).Methods: Forty-eight male aged SHR were randomly divided into three groups: control group(SC group), low dose propofol(SL group)and high dose propofol group(SH group). Forty eight male WKY were randomly divided into three groups too: control group(WCgroup), low dose propofol(WL group)ang high dose propofol group(WH group) .In groups SC and WC, after 0.9%NS. 1.2ml · kg-1 injection in 15 second,0.9%NS were administered continuously with the dose of 12ml · kg-1 · h-1;in groups SL and WL, after the induction with propofol 5mg· kg-1, 30mg· kg-1 · h-1 propofol were administered continuously; and in groups SC and WC,after the induction with propofol 5mg·kg-1, 60mg·kg-1 ·h-1 propofol were administered continuously . The same volumes were administered in three groups in both teams. Blood pressure and heart rate were monitored continuously. After infusion propofol for 30min or 60min,half of the rats in 6 groups were killed and Renin activity , angiotensin concentration in the blood , heart aorta and kidney were masured.The concentration of beta 2-microglobulin( β2-MG), uric acid in blood and urine ,endothelin(ET), calcitonin gene-related peptide (CGRP) in renal tissue and renal function were measured at time 60min.Results With the infusion of propofol ,blood pressure decreased and heart rate slowed down significantly in both SHR and WKY groups, the changes in SHR were more serious, and SHR were more sensitive to the dose. Renin activity , angiotensin concentration in the blood , heart aorta and kidney decreased in time 30min and 60 min. In group SB, WB and SC, WC urine volume decreased;creatinine clearance rate decreased significantly but without the alternation of renal function and changes of β 2-MG.The concentration of ET in renal tissue decreased significantly and CGRP increased significantly. The elimination of uric acid was increased.Conclusion (1)Propofol reduced blood pressure and slowed down heart rate in both age SHR and WKY.The changes in aged SHR were more obvious and aged SHR were more sensitive to the dose.(2) RAS were inhibited after propofol infusion which was related to the changes in hemodynamics.(3)Renal function of SHR were unchanged during propofol intravenous anesthesia despite it's inhibition on hemodynamics.In contrast,propofol intravenous anesthesia is appropriated for SHR due to it can increase the elimination of uric acid.