Fig. 3. Aequorin luminescence and force traces of isometric twitches during a typical Ca2+back- titration experiment for sevoflurane 2.7%. After an initial control (left ), muscles were exposed to sevoflurane 2.7% (middle ), and [Ca2+]owas rapidly increased (right ), so that peak developed force equaled that in control. At equal peak force, aequorin luminescence was higher in the presence of sevoflurane. Sixty-four twitches were averaged in each panel. The vertical arrow in each panel indicates the time of the electrical stimulus.