ABSTRACT
BACKGROUND: Propofol decreases arterial blood pressure. This has been ascribed to vasodilation and decreased cardiac output occuring separately or in combination. The goal of the present study was to assess the effects of propofol on the phenylephrine induced vasoconstriction in rat thoracic aortic rings. METHODS: All aortic rings were removed endothelium and isometric tension was recorded under a resting tension of 3 g. Isolated aortic rings were precontracted with phenylephrine (0.3micrometer) and propofol (1 to 100micrometer) was added cumulatively. We induced the phenylephrine preconstriction after treatment of verapamil 10micrometer in the other vascular rings. RESULTS: Propofol (1 to 100micrometer) attenuated phenylephrine (0.3micrometer) induced preconstriction dose-dependently. The administration of propofol (1 and 10micrometer) did not change the tonic constriction. The contractile response were significantly attenuated in verapamil pretreated rings but propofol did not affect on constriction in all dose range. CONCLUSIONS: Propofol attenuated phenylephrine precontracted rat thoracic aortic rings with inhibition of Ca2+ movement through the L-type calcium channel in the sarcolemmal membrane.
Subject(s)
Animals , Rats , Aorta, Thoracic , Arterial Pressure , Calcium Channels , Calcium Channels, L-Type , Cardiac Output , Constriction , Endothelium , Membranes , Muscle, Smooth, Vascular , Phenylephrine , Propofol , Vasoconstriction , Vasodilation , VerapamilABSTRACT
The effects of fentanyl pretreatment on controlling the hemodynamic changes during induc- tion have been compared in 58 adult normotensive patients undergoing elective operation. Two groups of 29 patients were observed. Patients were randomly assigned to receive thiopental 5 mg/kg alone(control group) or fentanyl 8 ug/kg pretreatment with thiopental 3 mg/kg (fentanyl group) for induction of anesthesia. The changes of mean arterial pressure(MAP), heart rate(HR), peak flow index(PFI), ejection Fraction(EF), end diastolic index(EDI), cardiac indx(CI) and stroke index(SI) were checked and compared with preinduction control values. The results were compared between two groups. The results were as follows. MAP and HR 1 minute after intubation increased significantly compared with preinduction values(p<0.001) in control group but showed minimal changes in the fentanyl group. The changes of PFI, EF, EDI, CI and SI showed decreasing tendencies after 30 seconds of thiopental injection in both groups, but the changes were small in the fentanyl group. Sinus tachycardia, premature ventricu1ar contraction, bigeminy were observed in both groups but the incidences were very low in the fentanyl group. It is suggested from the above results that fentanyl pretreatment(8ug/kg) reduces the hemo- dynamic changes during induction of general anesthesia and is more safe method for induction of cardiac or cerebrovascular disease patients.