title: Endogenous opioids in cerebrospinal fluid of opioid-dependent humans.
abstract: Endogenous opioid systems may be altered as a consequence of addiction, but evidence to support this idea is meager so far. We obtained 136 cerebrospinal fluid (CSF) samples from 72 opioid addicts during four distinct states: methadone maintenance, detoxification from methadone, opioid antagonist treatment, and drug-free status. CSF endorphins were measured in 86 patients samples using a radioreceptor assay (RRA), and beta-endorphin levels were measured in 85 patient samples using a radioimmuno assay (RIA). During detoxification, both RRA fraction I and beta-endorphin showed a generally similar pattern of changes. Both were lowest when measured 40-50 hr after the last opioid dose, and both showed an apparent rebound to higher than methadone maintenance values at 60-70 hr following the last dose. During methadone maintenance and drug-free states, the addicts' levels of fraction I RRA endorphins in the CSF were higher than levels found in a normal control group. Fraction II endorphins were also elevated in the addicts who were drug free. In contrast, CSF beta-endorphin during both methadone maintenance and drug-free states was lower in the addicts as compared to the normal, drug-naive group. Except for the pattern found during detoxification, there were no consistent changes in endorphin levels across different states of addiction.
authors.affiliation: Veterans Administration Medical Center, University of Pennsylvania, Philadelphia 19104.
authors.forename: C P
authors.initials: CP
authors.lastname: O'Brien
authors.forename: L Y
authors.initials: LY
authors.lastname: Terenius
authors.forename: F
authors.initials: F
authors.lastname: Nyberg
authors.forename: A T
authors.initials: AT
authors.lastname: McLellan
authors.forename: I
authors.initials: I
authors.lastname: Eriksson
mesh_terms: D000328:Adult; D006556:Heroin Dependence / Q000134:cerebrospinal fluid* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use; D009271:Naltrexone / Q000627:therapeutic use; D011863:Radioimmunoassay; D011869:Radioligand Assay; D011957:Receptors, Opioid / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000134:cerebrospinal fluid; D001615:beta-Endorphin / Q000134:cerebrospinal fluid*
chemical_list: D011957:Receptors, Opioid; D009271:Naltrexone; D001615:beta-Endorphin; D008691:Methadone