Ether-induced vasodilation in the rat.

The hypotensive effect of ether in rats was investigated by the direct Fick technique to determine whether hypotension was produced by reduced cardiac output or decreased total peripheral resistance. Relative to the conscious state, ether anesthesia decreased mean arterial pressure 9%, total peripheral resistance 47%, oxygen extraction 37%, and heart rate 7%; changes were qualitatively similar to those produced by hydralazine (0.5 mg/kg, i.v.) except that hydralazine did not decrease heart rate. These effects were no longer present two hours after withdrawal of ether. This study demonstrated that ether anesthesia in rats has a potent systemic arterial vasodilating action which is offset by increased cardiac output, resulting in mild hypotension.