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. Author manuscript; available in PMC: 2008 Jun 1.
Published in final edited form as: Biochem Pharmacol. 2007 Feb 12;73(11):1818–1828. doi: 10.1016/j.bcp.2007.02.001

Figure 3.

Figure 3

Receptor binding in opioid treated mu opioid receptor expressing CHO cells. Cells were exposed in culture to 20 μM morphine, 10 μM methadone, or 5 μM (-)- or (+)-methadone for 3 h to 48 h. Homogenized membrane preparations were assayed for their ability to bind [3H]-diprenorphine (0.6 nM). Receptor binding is plotted as percent of untreated control. Data is mean ± S.E.M of three independent experiments performed in triplicates. No significant changes in receptor binding were observed for chronic morphine or (+)-methadone treatment. Both rac- and (-)-methadone caused reduced receptor binding after 3 h of exposure that was sustained up to 48 h (P < 0.001 vs. control). No statistical differences were found after 12 h of treatment for each drug.