Fig. 1. Tracings showing the effect of different concentrations of halothane on pCa 6.3–induced force. 0%, 1%, 2% , and 3% = concentrations of halothane from four different arterial strips. Each preparation was activated with pCa 6.3 buffer, which was changed once (shown with an exchange artifact). When the force generated by pCa 6.3 reached a steady state (control), another fresh pCa 6.3 buffer saturated with one of the halothane concentrations was administered, and the result was observed for up to 60 min (test). The tracings show that halothane decreases pCa 6.3–induced force, which is increased with increased halothane concentrations from 1 to 3%.