Figure 2.
Freeze-fracture replica immunolabeling of Munc13-1 and Cav2.1 in excitatory synapses on Kv3.1b+ and mGluR1α+ INs
(A) Low magnification image of the protoplasmic membrane face (PF) of a Kv3.1b+ dendrite (dendritePF) targeted by three excitatory boutons (bEF) with fully exposed AZs (highlighted in orange).
(B) The mirror replica of that shown in (A) immunolabeled for Munc13.1 and Cav2.1. Gold particles are concentrated in the AZs (orange) on the PF membrane of the boutons (bPF).
(C and D) High magnification images of the boxed areas in (B) showing a small (C) and a large (D) AZ. Gold particles are highlighted in blue (Munc13-1) and purple (Cav2.1).
(E–N) Low (E, F, H, I, K, L) and high (G, J, M, N) magnification replica images immunolabeled for mGluR1α, Munc13-1, and Cav2.1. (E) and (F), (H) and (I), (K) and (L), and (M) and (N) are mirror replica images of the same dendrites. AZ areas are shown in cyan; gold particles are highlighted in blue (Munc13-1) and purple (Cav2.1).
(O) Delineated AZs on Kv3.1b+ (orange) and mGluR1α+ (cyan) dendrites (original images shown in C, D, G, J, and N) showing gold particles labeling Cav2.1 (purple) in relation to Munc13-1 clusters (blue). Clustering was performed with DBSCAN.