Differential expression of CB₁R-5-HT_2AR heteromers in the brain detected by in situ PLAs.

<p>In (A), PLAs were performed using slices of mouse hippocampus CA3, caudate-putamen (striatum), cortex (somatomotor layers 1, 2, and 3) or nucleus accumbens (NaC). Confocal microscopy images (superimposed sections) are shown in which heteromers appear as green spots in WT mice, but not in 5-HT_2AR KO or CB₁R KO mice in the hippocampus, caudate-putamen, and cortex. Any staining was observed in the nucleus accumbens of either WT or KO animals. In all cases, cell nuclei were stained with DAPI (blue). Scale bars = 20 μm. In (B), the number of cells containing one or more green spots is expressed as the percentage of the total number of cells (blue nucleus) in the hippocampus, striatum, cortex, and nucleus accumbens of WT (white bars), 5-HT_2AR KO (black bars), or CB₁R KO (grey bars) mice. Data (percentage of positive cells) are the mean ± SEM of counts in 4–9 different fields (see experimental procedures). Student’s <i>t</i> test showed a significant effect over 5-HT_2AR KO or over CB₁R KO mice in each condition (*** <i>p</i> < 0.001).