Figure 2.

Ultrastructural localization of CB₁ receptors in mitochondrial sections with the immunoperoxidase DAB–Ni method using a goat anti-CB₁ C-ter31 antibody. (A–C) In CB₁-WT mouse, CB₁ immunoreactivity was observed in mitochondrial sections (asterisks), some of them were contained in CB₁-positive synaptic terminals (black immunoreaction product). (D and E) Absence of CB₁ immunodeposits in mitochondrial sections and synaptic terminals of CB₁-KO mouse. Only some scattered mitochondrial sections display DAB–Ni precipitates (asterisk in E). (F and G) Unspecific immunodeposits on mitochondrial sections (asterisks) and dendritic profiles of CB₁-KO mouse when the primary antibody was omitted. (H) Semi-quantitative analyses of the proportion of CB₁ immunopositive mitochondrial sections in CB₁-WT and CB₁-KO mice, and in CB₁-KO mice without primary antibody. (I) Semi-quantitative analyses of the proportion of CB₁ immunopositive mitochondrial section in CB₁-WT and CB₁-KO mice after subtraction of the percentage value obtained in CB₁-KO mice without primary antibody. Data are expressed as mean ± S.E.M. ***p < 0.0001 according to chi-square test. ter: presynaptic terminals; den: dendrites; sp: dendritic spines. Scale bars: 0.5 μm.