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Practical Applications Of Neuroscience Research February 16, 2007 Charles P. O’Brien, MD, PhD University of Pennsylvania Philadelphia VA Medical Center
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Search: Non-addicting med for severe pain NIH (NIDA) Opiate Receptors 1973 Endogenous opioids “endorphins” Enkephalin 1975 ∂ B-Endorphin µ Dynorphin k Nociceptin OFQ/NOC 1990’s
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Post-Synaptic Neuron Kappa Mu Delta Affinity for Opiate Receptor TX TX TX TX Opiate Receptors Kappa Mu Delta Naltrexone 406 108 54 Naltrexone 406 108 54 Morphine 1 1 1 Morphine 1 1 1 MOR MOR MOR MOR.. NOC N
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New Concepts: agonist antagonist partial agonist inverse agonist
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Opiate receptor antagonists 1970s Naloxone reverse opiate analgesia treat opiate overdose Naltrexone block heroin relapse (FDA 1984) treat babies born with excess endorphins treat form of infertility by stimulating gonadotrophins
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Naltrexone treatment of opiate addiction Little use for heroin addiction Treatment of choice for physicians and other “white collar” addicts Successful treatment of parolees and probationers Block revolving door: heroin-prison-heroin
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SubstanceOral Nltx Control Sig. (N=34) (N=17) (N=34) (N=17) Opiate8%30%p<.05 Cocaine33%49%NS Amphetamine0%1%NS Benzodiazepine2%6%NS Marijuana13%19%NS Alcohol2%4%NS Parolees Mean Percent Positive Urines
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Re-Incarceration at 6 months NaltrexoneControl Percent subjects 26% 56% P<.05
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Study in Parolees with History of Opiate Addiction Six sites Providence, RI NYC (Columbia) NYC (NYU) Philadelphia Baltimore Richmond Relapse Rate to Heroin Addiction Re-incarceration Rate
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Alcohol stimulates endogenous opioids Unexpected finding from animal models Monkeys 1979 Rats 1980s First study in human alcoholics, Philadelphia VAMC 1983-90 Family history positive alcoholics Opiate-like euphoria from alcohol High craving for alcohol
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Subjective “high” in Naltrexone and Placebo Subjects Subjective “high” in Naltrexone and Placebo Subjects Naltrexone Placebo mean “high” rating 0.1 0 - 0.1 - 0.2 - 0.3 - 0.4 - 0.5 * * p<.05
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Non-relapse “Survival” Volpicelli et al, Arch Gen Psychiatry, 1992; 49: 876-880 No. of Weeks Receiving Medication 1023456789101112 0.0 0.1 0.2 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.3 Naltrexone HCL (N=35) Placebo (N=35) Cummulative Proportion with No Relapse
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Rates of Never Relapsing According to Treatment Group (n=97) O’Malley et al, Arch of Gen Psychiatry, Vol 49, Nov 1992 Naltrexone/coping skills Naltrexone/supportive therapy Placebo/coping skills Placebo/supportive therapy Days 0 20 40 60 80 100 n=97 020408060
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Naltrexone treatment of alcoholism Philadelphia VA results replicated 1992 FDA approval 1994 Naltrexone used throughout the world for alcoholism Does not work for all alcoholics
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Genetics of alcoholism Genetic variant of µ opiate receptor “G allele” Increased euphoria from alcohol Euphoria blocked by Naltrexone Increased risk of opiate addiction Increased risk of alcoholism G allele: 20-25% of European-Americans Poor outcome randomized to placebo treatment & counseling Excellent results with naltrexone & counseling
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Relapse Rate by Genotype
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Replication study Nalt A/G, GG95%N = 28 Nalt A/A73%N = 86 Plac. A/G, GG63%N = 60 Plac. A/A65%N = 205 Odds ratio, nalt good regs, GVA = 10.25 (95% CI 1.31 - 80.0 P=.03) “Good” Results
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New delivery system One injection each month Slow release Blocks opiates and endogenous opioids for one month Alcoholism: FDA approved 2006 Opiate addiction: in clinical trial
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Summary Search for non-addicting pain reliever Discovery of opiate receptors Discovery of endogenous opioids Development of opiate antagonists New treatment for opiate addiction New treatment for alcoholism Endophenotype of alcoholism ? Reduced re-incarceration of heroin addicts
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Institutionalization in the United States (per 100,000 adults) Total RatePrison RateMental Hospital Rate ___ Total Rate __ __ __ Prison Rate _ _ _ Mental Hospital Rate
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