Research on drug abuse and addiction has become increasingly multi-disciplinary and many laboratories do not have all the necessary techniques to approach projects of interest in a comprehensive manner. The Core has filled a niche where researchers who do not or cannot perform biochemical pharmacology experiments can come for help. The Core performed state-of-the-art biochemical pharmacology assays, thereby saving researchers both valuable time and resources. From our experience in the past several years, most researchers who used the Core are either behavioral scientists, such as Dr. Julie Blendy of University of Pennsylvania, or chemists such as Drs. David Y.-W. Lee, Cecile Beguin, and Bruce Cohen of McLean Hospital, Harvard Medical School. These researchers either do not have biochemical pharmacology expertise or can not afford to buy the equipment to establish the techniques. The services provided by the Core are valuable to these researchers and have resulted in many publications (see Progress Report). Some have turned into long-term collaborations, for example, the work with Dr. David Y.-W. Lee, Dr. Bruce Cohen and Dr. Julie Blendy. The Core has provided preliminary results for grant applications and one was funded. The second type of work is short-term in scope. For example. Dr. William Cariezon's lab generated constitutive KOPR knockouts and conditional knockouts that lack KOPRs in dopamine-containing neurons. The Core performed autoradiography of [3H]U69,593 binding to the KOPR in brain sections to verify the deletion (76). The third type of work is exploratory in nature. For example. Dr. Robishaw's group generated a mutant mouse line with deletion of the gene of the Y3 subunit of the trimeric G proteins (Gng3-/-). Gng3(-/-) mice showed marked reductions in both acute and chronic morphine responsiveness (71). The Core performed MOPR-mediated [35S]GTP?S binding to membranes of brain regions and found no significant differences between the wildtype and mutant mice. All these services are cost-effective in that these labs did not have to devote time and effort to establish the techniques and, in some cases, get negative results. It has been difficult, if not impossible, to get good antibodies for seven transmembrane receptors (7TMRs) (7, 22, 32, 34, 49, 57, 66). Dr. Liu-Chen's lab generated rabbit antiserum against a mu opioid receptor (MOPR) C-terminal domain peptide and purified it with peptide affinity chromatography. Her group found that the purified antibodies (anti- ?C) worked well in immunoblotting of endogenous MOPR in the rat and mouse brain (26, 30). Dr. Ping-Yee Law has used the antibodies for several studies (18, 67, 92-94). However, several other labs were not successful in MOPR immunoblotting using the same antibodies. The Core will assist researchers in performing the initial immunoblotting of endogenous MOPR to assess the feasibility and, if feasible, the Core will train personnel in these labs. In addition, the core will distribute the antibodies to researchers who are interested (in small quantity due to limited supply). Although initially the work was one directional, i.e. the Core did work for researchers, some have turned into bi-directional collaborations. For example. Dr. David Lee's group isolated l-tetrahydropalmatine (l-THP) and l-isocorypalmine (I-ICP) from the herb Corydalis yanhuso (50). L-THP has been used in China for 40 years as an analgesic with sedative effect (33). It was found to be effective in treatment of heroin addiction in China (90). It is currently in a NIDA-supported clinical trial in the US for cocaine addiction. Although some in vivo effects appear to be mediated by dopamine receptors (33), The Core found that it had low or no affinity for all five dopamine receptors, neither did it bind to about 50 neurotransmitter receptors, ion channels, and transporters involved in pain modulation and drug addiction (88). In contrast, its demethylated analogs including 1-lCP have significant affinity for dopamine receptors (88). Dr. Lee and Dr. Liu-Chen thus hypothesized that l-THP is a pro-drug and its actions are due to its metabolites. They submitted an application and were awarded a grant from NCCAM in 2012 to study the mechanisms of action of L-THP.
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