RT Journal Article
SR Electronic
T1 Buprenorphine Is a Weak Partial Agonist That Inhibits Opioid Receptor Desensitization
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 7341
OP 7348
DO 10.1523/JNEUROSCI.3723-08.2009
VO 29
IS 22
A1 Virk, Michael S.
A1 Arttamangkul, Seksiri
A1 Birdsong, William T.
A1 Williams, John T.
YR 2009
UL http://www.jneurosci.org/content/29/22/7341.abstract
AB Buprenorphine is a weak partial agonist at μ-opioid receptors that is used for treatment of pain and addiction. Intracellular and whole-cell recordings were made from locus ceruleus neurons in rat brain slices to characterize the actions of buprenorphine. Acute application of buprenorphine caused a hyperpolarization that was prevented by previous treatment of slices with the irreversible opioid antagonist β-chlornaltrexamine (β-CNA) but was not reversed by a saturating concentration of naloxone. As expected for a partial agonist, subsaturating concentrations of buprenorphine decreased the [Met]5enkephalin (ME)-induced hyperpolarization or outward current. When the ME-induced current was decreased below a critical value, desensitization and internalization of μ-opioid receptors was eliminated. The inhibition of desensitization by buprenorphine was not the result of previous desensitization, slow dissociation from the receptor, or elimination of receptor reserve. Treatment of slices with subsaturating concentrations of etorphine, methadone, oxymorphone, or β-CNA also reduced the current induced by ME but did not block ME-induced desensitization. Treatment of animals with buprenorphine for 1 week resulted in the inhibition of the current induced by ME and a block of desensitization that was not different from the acute application of buprenorphine to brain slices. These observations show the unique characteristics of buprenorphine and further demonstrate the range of agonist-selective actions that are possible through G-protein-coupled receptors.