Fig. 7. O₂ consumption of G. dibranchiata erythrocytes under control conditions or exposed to the mitochondrial COX inhibitors sodium azide (1 mmol l^-1) and sodium cyanide (1 mmol l^-1). Values are means ± S.D. (N=5 for CN, N=3 for azide). O₂ consumption is presented relative to the average at control conditions (i.e. consumption rate immediately prior to addition of inhibitor). Asterisks represent a significant decrease in consumption rate to the control value (no toxin) by one-tailed, paired t-test (^**P<0.01, ^***P<0.005).