(A-C) Alignment of SSDs of pre-synaptic RIM1/2 and SSDs of post-synaptic gephyrin, GlyRs, and GABAARs, respectively. (A1-C1) Distances were measured between the intensity peaks of paired SSDs in rendered dual-color dSTORM images (yellow line, values given in mean ± SD). RIM1/2 was labelled with Alexa 647 and gephyrin (mAb7a) with Cy3B in (A1). RIM1/2 was labelled with Cy3B, while GlyRs or GABAARs were labelled with Alexa 647 in (B1) and (C1). (A2-C2) Trans-synaptic alignment of SSDs of gephyrin, GlyRs, GABAARs and RIM1/2. SSDs were segmented by H-watershed. Data are plotted as mean ± SD. Number of synapses: n = 48 (A1, A2) from three independent experiments (no treatment), n = 30 (B1, B2) from two experiments with TTX treatment, n = 16 (C1, C2) from two experiments with TTX. Only synapses with side view profiles were included. All images are adjusted to the same scale. Scale bar: 200 nm. 