The most frequently observed co-expression was between CHRM3 and GABRG2, which was seen in eight brain tissues (all P-values < 1 × 10−10 and r2 ≥ 0.6). CHRM3 was also significantly co-expressed with CHRNA4 and HRH3 in THAL (both P-values < 1 × 10−10 and r2 ≥ 0.7), and with HRH3 (P-value < 1 × 10−10 and r2 = 0.6) in PUTM. Furthermore, at the single-cell level, the homologous mouse genes Chrm3 and Gabrg2 were significantly co-expressed with one another in six different GABAergic neuronal cells (all P-values < 1 × 10−5 and r2 ≥ 0.6), whereas Hrh3 and Chrna4 were both significantly co-expressed with Chrm3 at least in three different GABAergic single neurons (all P-values < 1 × 10−5 and r2 ≥ 0.4). Taken together, these results show that CHRM3 is strongly co-expressed with GABRG2, HRH3, and CHRNA4 (risk genes for psychotic disorders, epilepsy, and schizophrenia) in THAL and other brain tissues.
