DPDPE-UK14,304 synergy is retained in mu opioid receptor knockout mice

Abstract
When agonists to α2adrenergic receptor (AR) and δ opioid receptor (DOR) are co-administered, they act synergistically to inhibit nociceptive elicited behavior. Some previous studies of synergism have used the DOR-selective agonist [d-Pen2,d-Pen5]-enkehphalin (DPDPE), however, DPDPE has been