Fig. 8. Nonadditivity of effects of phorbol 12-myristate 13-acetate (PMA) with propofol or isoflurane on tyrosine phosphorylation in rat hippocampal slices. Data (mean ± SD) are expressed as a fractional increase from basal phosphorylation (control = 100%). The anesthetics and pharmacologic agents were used at the following concentrations: 0.1 μm PMA, 5 μm propofol, 0.2 mm isoflurane. P < 0.01 and ** P < 0.01 versus control.