Figure 7

Effect of the citrate cycle intermediates succinate, fumarate and malate on HPV. (A) Addition of succinate nearly completely blocked HPV. Significant differences between the succinate and the control group in their response to U46619 were noted when the data were standardized to the luminal areas recorded at the beginning of hypoxic exposure, as depicted here, but not when data were standardized to the luminal areas recorded at the end of the post-hypoxic wash period. (B) Addition of fumarate delayed the hypoxic response and was without significant effect on U46619-induced vasoconstriction. (C) Malate inhibited both HPV and U46619-induced vasoconstriction. Data are presented as means ± SEM. *p = 0.05, ** p = 0.01, n.s. = not significant.