Deltorphin II is a peptide agonist of δ2-opioid receptors.1,2It is selective for δ-opioid receptors over μ- and κ-opioid receptors in radioligand bindings assays (Kis = 0.0033, >1, and >1 μM, respectively) and induces [35S]GTPγS binding in mouse brain membrane preparations (EC50= 0.034 μM). Deltorphin II (0.12 mg/kg) decreases the infarction zone:risk zone ratio in a rat model of myocardial ischemia-reperfusion injury induced by coronary occlusion, an effect that can be reversed by the δ2-opioid receptor antagonist naltriben but not the δ1-opioid receptor antagonist BNTX.3Intrathecal administration of deltorphin II (15 μg/animal) increases latency to withdraw in the paw pressure and tail-flick tests in rats.4

Deltorphin II (trifluoroacetate salt)

DMF:15 mg/mL
DMF:PBS (pH 7.2) (1:5):0.16 mg/mL
Ethanol:Slightly soluble
DMSO:1 mg/mL
Powder: -20°C for 3 years
In solvent: -80°C for 2 years