Fig. 1. Dose dependence of respiratory stimulation by bupivacaine enantiomers. Stimulated oxygen consumption (with 10 mm pyruvate plus 10 mm malate), J–Jo, is plotted as a function of anesthetic concentration. J and Jo are rates of respiration (nmol oxygen · min⁻¹· mg mitochondrial protein⁻¹) in the presence and absence of the drug, respectively. Jo was between 40 and 50 nmol oxygen · min⁻¹· mg protein⁻¹with this assay medium. Values presented are from five experiments conducted with five mitochondrial preparations and are expressed as mean ± SD.