Figure 6. The concentration response curves of the effect of isoproterenol on cyclic adenosine monophosphate (cAMP) content of isolated cardiomyocytes in the absence ([square, open]) and in the presence ([square bullet, filled]) of a 3 vol% halothane atmosphere. All values are given with 95% confidence intervals. Ordinate = cAMP level in picomoles per milligram of protein; abscissa = the molar concentration of isoproterenol.