Fig. 4

Normal mitochondrial content at presynaptic MF boutons of PS cDKO mice. a Transmission electron micrographs of hippocampal stratum lucidum in area CA3 show large presynaptic mossy fiber boutons (MFB: highlighted in yellow) establishing synaptic contacts with large complex spines (asterisks) of CA3 pyramidal neuron dendrites (D). The arrowheads indicate mitochondria in the MFB. Scale bars: 1 μm. The randomized samples were obtained from at least 10 micrographs from each of the 4 mice per genotype. b-d Quantification of the number of mitochondria per bouton (control: 10.02 ± 0.33, PS cDKO: 9.51 ± 0.33, n = 59 boutons), total mitochondrial area per bouton (control: 0.42 ± 0.04 μm², n = 44; PS cDKO: 0.49 ± 0.04 μm², n = 42), and bouton area (control: 6.04 ± 0.45 μm², n = 59; PS cDKO: 6.41 ± 0.58 μm², n = 42). The data are presented as means ± SEM (NS: not significant, Student’s t-test)