Fig. 3.

Density gradient and distribution profile of immunoparticles labelling GABA_B1 along the surface of PCs. a Density of GABA_B1 immunoparticles (including both isolated particles and those within small aggregations) increased from soma to distal dendrites (soma = 8.71 ± 1.43/μm²; apical dendrite = 79.14 ± 18.98/μm²; oblique dendrite = 175.33 ± 34.63/μm²; spines = 227.62 ± 102.18/μm²; Kruskal–Wallis test, pairwise Mann–Whitney U test and Dunn’s method, *p = 0.003; **p < 0.001). b The graph shows the quantification for the size of GABA_B1 clusters in the spines, oblique dendrites and apical dendrites. Approximately 75% of clusters consisted of 3–8 immunoparticles. c Example showing random simulation of GABA_B1 immunoparticles in a dendritic spine. Red: real GABA_B1; Yellow: simulated GABA_B1; blue: real GIRK2. Scale bar: 100 nm. d Cumulative probability plots of GABA_B1 to GABA_B1 NND. Solid and dotted lines show real and simulated GABA_B1, respectively. AZ active zone. e–g Positive linear correlation was found between the number of GABA_B1 immunoparticles and the area of clusters in the three dendritic compartments [spines, oblique dendrites (Ob Den) and apical dendrites (Ap Den)]