These authors also investigated the subcellular distribution of the CB1 receptor using electron microscopy (EM)(Katona et al., 2001). Within the BLA, immunogold labeling was observed within intracellular membrane compartments including rough endoplasmic reticulum and golgi. In addition, multivesicular bodies were densely labeled. Furthermore, no staining was observed on either the plasma membrane of cell bodies or proximal dendrites. Densely labeled axon terminals were also observed using immunogold labeling on the intracellular surface. These axon terminals formed symmetric, presumably GABAergic, contacts with somata and dendritic shafts. CB1-expressing terminals were also found to co-express CCK and form exclusively symmetric synapses (Katona et al., 2001).
