OPRK1 and depressive disorder: Both receptors are types of G Protein-Coupled Receptors (GPCRs), and the \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$A_{2A}R$$\end{document}A2AR is involved in the treatment of conditions such as insomnia, pain, depression, Parkinson’s disease, cardiovascular diseases, and inflammatory disorders [19], while the KOR mediates pain, mood, and motor control.