“…␦R expressed in nociceptive neurons can reduce cAMP and inhibit Ca 2ϩ channels to inhibit neuronal activity (Jutkiewicz et al, 2006;Cahill et al, 2007;Pradhan et al, 2011;Bardoni et al, 2014). ␦R agonists can cause antinociception in some conditions, and they show reduced abuse liability compared with current opioids that target the opioid receptor (R) ( Vanderah, 2010;Gendron et al, 2016). ␦R-mediated antinociception in vivo, however, requires high doses approaching concentrations that cause serious adverse effects (Danielsson et al, 2006;Jutkiewicz et al, 2006;Pradhan et al, 2011;Gendron et al, 2016).…”