Fig. 4

Mitochondrial activity and membrane potential in HMBS-deficient mice. Measurement of the relative enzymatic activity (ratio to citrate synthase as housekeeping enzyme) of the four respiratory chain complexes in the hippocampus in a CI, b CII, c CIII and d CIV; a-dn = 9–10 per genotype. TMRM assay of e the basal TMRM fluorescence in cultured hippocampal neurons obtained from WT mice and KI mice. f Response of TMRM fluorescence to ATP synthase inhibitor Oligomycin, complex III inhibitor Antimycin A and protonophore FCCP in primary hippocampal neurons of KI and WT mice; e-fn = 9–12 per genotype. All values are presented as mean ± SEM. Statistical significances displayed are results of Student’s t-test. **p < 0.01, ***p < 0.001; HMBS, hydroxymethylbilane synthase; CI-IV, mitochondrial complex I-IV, TMRM, tetramethyl rhodamine ethyl ester, FCCP, carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone