Fig. 3. Succinate-dependent respiration at increasing halothane concentrations. (  A ) The effect of halothane on state 3 respiration  via complex II. Respiration is consistently higher in  gas-1(fc21) mitochondria than in N2 mitochondria and is relatively resistant to halothane. (  B ) The effects of halothane on state 4 respiration with N2 and  gas-1(fc21) mitochondria. State 4 respiration was not significantly increased by halothane, even at high doses, ruling out halothane functioning as an uncoupler. (  C  ) Phosphorylation in N2 and  gas-1(fc21)  mitochondria in increasing halothane concentrations. As with state 3 respiration, phosphorylation is consistently higher in  gas-1(fc21)  mitochondria than in N2 mitochondria.  Bars and  error bars represent means and SDs, respectively. n = number of repeats for each experiment (n =3 for N2; n =4 for  gas-1 ).