In this study, the authors show that there are multiple forms of opioid-induced long-term depression (OP-LTD) in the dorsal striatum, each mediated by the mu, delta or kappa opioid receptor. The mu and delta OP-LTD are presynaptic and can summate, but only mu OP-LTD occludes endocannabinoid-induced LTD. Furthermore, mu OP-LTP, but not kappa or delta OP-LTP, is blocked by the analgesic oxycodone.
- Brady K Atwood
- David A Kupferschmidt
- David M Lovinger
