Figure 2. Time-dependent effects of 5 micro Meter epinephrine (EPI) with 0.45 mM halothane (HAL) on conduction velocity before (ten preparations) (top) and after (five preparations each) (bottom) alpha sub 1 - and beta¹-adrenergic blockade. PRAZ = prazosin; MET = metoprolol. *P less or equal to 0.01 versus halothane alone (at time 0).