Opioids are pain treatment mainstays, but present with potentially lethal respiratory depression. To develop safer opioid therapies, mechanisms underlying opioid-induced respiratory depression must be better understood. Opioids mainly bind to µ-opioid receptors (MORs), Gprotein-coupled receptors that activate heterotrimeric G-proteins, including Gβγ. There is significant debate around whether G-proteins or β-arrestins, proteins involved in receptor internalization/desensitization, directly regulate respiratory circuit inhibition. While Gβγ activates G-protein inwardly rectifying potassium (GIRK) channels, which are key mediators of respiratory rate depression, its direct role in opioid-induced respiratory depression is unknown. We investigated the contribution of Gβγ in opioid-induced respiratory rate depression and found Gβγ inhibition in respiratory circuits reversed opioid-induced respiratory rate depression, regulators of
G-protein signaling 4 (RGS4) are co-expressed with MORs in respiratory circuits, and RGS4 inhibition in vivo potentiates opioid-induced respiratory rate depression. Our data suggest G-protein signaling is key in opioid-induced respiratory depression and is not limited to β-arrestin recruitment.M.Sc
