BW373U86

(+)BW373U86 is an opioid analgesic drug used in scientific research.

BW373U86 is a selective agonist for the δ-opioid receptor, with approximately 15x stronger affinity for the δ-opioid than the μ-opioid receptor. It has potent analgesic and antidepressant effects in animal studies, and triggers release of the neural growth factor BDNF, but its usefulness is limited by producing convulsions at high doses,  although the convulsive effect is reduced when it is co-administered with μ-opioid agonists. Another advantage of the combination is that BW373U86 reverses the respiratory depression produced by μ-opioid agonists, without affecting pain relief.

Another useful effect of BW373U86 is that it protects heart muscle cells from death in conditions of ischemia (oxygen deprivation, such as in heart attack). The mechanism for this is complex and may be separate from its delta agonist effects.