We also employed immunohistochemistry, RT-qPCR, and ELISA to evaluate gene and protein expression levels in dorsal root ganglia (DRG) and skin tissues, including a mouse model of atopic dermatitis (AD).<h4>Results</h4>OPRM1 formed heterodimers with MRGPRX1 in HEK293T cells and sensory neurons, triggering a signaling switch from Gα<sub>i/o</sub>-mediated cAMP inhibition to Gα<sub>q/11</sub>-driven calcium mobilization upon activation with DAMGO or endogenous opioids. This evidence concerns the gene OPRM1 and Alzheimer disease.