We studied the effects of three anesthetic agents on the central hemodynamics of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats instrumented with chronic electromagnetic flow probes and arterial pressure catheters. Cardiovascular alterations due to ether, pentobarbital sodium (PBS; 50 mg/kg), and a 2% chloralose-7.5% urethan mixture (CU; 6 ml/kg) were determined. Ether produced significant elevations in heart rate (HR), cardiac index (CI), stroke volume (SV), and peak aortic flow velocity (PAFV) in SHRs (P less than 0.01) and elevations of HR and CI in WKYs (P less than 0.05). Ether reduced total peripheral resistance (TPR) and mean arterial pressure (MAP) in WKYs and SHRs (P less than 0.01). PBS decreased HR, CI, SV, MAP, PAFV, and minute work (MW) in both WKYs and SHRs (P less than 0.05--P less than 0.001). PBS also lowered TPR in WKYs (P less than 0.05). CU produced effects similar to those of PBS, but did not alter HR or TPR. Central hemodynamics are therefore significantly altered by these anesthetics when compared to those of conscious rats. These agents also have differential effects on the hemodynamics of SHRs and WKYs.