The Experts below are selected from a list of 3378 Experts worldwide ranked by ideXlab platform
Nora D Volkow - One of the best experts on this subject based on the ideXlab platform.
-
further evidence that naloxone acts as an inverse Opiate Agonist implications for drug dependence and withdrawal
Life Sciences, 1996Co-Authors: Silvia L Cruz, Julian E Villarreal, Nora D VolkowAbstract:Abstract To test if naloxone behaved as an inverse Agonist rather than as an antAgonist we evaluated its responses in guinea-pig ilea with and without morphine (480 nM, 24 h). In control ilea, naloxone (100 nM) had no effect. In morphine-treated ilea, naloxone as a bolus, but not as an infusion, elicited an abstinence response. Preadministration of naloxone blocked the response to subsequent administrations. Similarly, naloxone failed to produce an abstinence response in ilea pretreated with kappa compounds (bremazocine, U50488 or xorphanol 100 nM) or with kinase inhibitors (H7 or H8 30 μM). These findings can be interpreted in the light of the two-state receptor model if naloxone behaves as an inverse Agonist: Incubation with morphine increased the active state of receptors making them susceptible to the inverse Agonist (naloxone); exposure to naloxone favored the inactive conformation making them insensitive to further administration of naloxone; kappa compounds behaved as antAgonists preventing the response to naloxone; and kinase inhibitors interfered with the active conformation making the system insensitive to naloxone. According to this model, dependence can be viewed as an overexpression of the active receptors and withdrawal as an abrupt change from the active to the inactive state.
Edward Gignoux - One of the best experts on this subject based on the ideXlab platform.
-
dissolution of a harm reduction track for Opiate Agonist treatment longitudinal impact on treatment retention substance use and service utilization
International Journal of Drug Policy, 2010Co-Authors: Bryan Hartzler, Ann J Cotton, Donald A Calsyn, Rachael Guerra, Edward GignouxAbstract:Abstract Background There is great need to sustain harm reduction programmes for Opiate-dependent persons, given variable retention of opioid Agonist treatment (OAT) enrolees. Resource challenges may lead some health organizations to discontinue such programmes, though just as programmatic evaluation may determine efficacy and cost-effectiveness so to does it aid in examining impacts of programme dissolution. Methods This retrospective evaluation investigated impacts of the dissolution of a ‘Minimal Services' (MS) harm reduction programme for substance-abusing OAT clientele at an urban U.S. Veterans Affairs Medical Centre. Targeted clinical data concerning treatment retention, substance use and service utilization was abstracted from medical records of MS-assignees ( N =32) and a matched comparison group of standard OAT enrolees. Chart reviewers gathered data for a two-year period encompassing baseline, transitional, and dissolution study phases. Results Relative to matched-controls, MS-assignees exhibited: (1) disproportionately poor treatment retention over the two-year period; (2) high and temporally stable rates of documented substance use across study phases, and (3) increased utilization of resource-laden VAMC services after MS dissolution. Conclusion Collective results suggest MS programme dissolution was associated with adverse conditions for assignees and the larger treatment setting, and reinforce the need for pragmatic, humane treatment policies to facilitate retention of Opiate-dependent persons.
Morten Hesse - One of the best experts on this subject based on the ideXlab platform.
-
easy access services in low threshold Opiate Agonist maintenance
International Journal of Mental Health and Addiction, 2008Co-Authors: Morten Hesse, Mads Uffe PedersenAbstract:Background There is currently evidence that methadone and buprenorphine maintenance is effective in reducing substance abuse. However, it is not known whether psychosocial support improves the outcome of methadone maintenance in the absence of control measures, such as regular urine testing.
-
The Beck Depression Inventory in patients undergoing Opiate Agonist maintenance treatment
British Journal of Clinical Psychology, 2006Co-Authors: Morten HesseAbstract:Background and objectives. The Beck Depression Inventory (BDI) is a widely used measure of depression severity in both research and clinical contexts. This study aimed at assessing its stability and associations with ongoing drug use in a sample of patients in Opiate Agonist maintenance treatment who were not abstinent from illicit drugs. Design and method. The study was a prospective, naturalistic study. Subjects in enhanced or standard psychosocial services along with Opiate Agonist maintenance treatment were administered the BDI and the European Addiction Severity Index (EuropASI) twice by research technicians, approximately 2 weeks after intake and at 18 months follow-up. Findings. There were rather small mean changes from intake to follow-up in the BDI, and mean-level stability in subjects was rather high as evidenced by a high intra-class correlation between intake score and follow-up score. The stability of the BDI was reduced at high levels of drug use severity at intake, and BDI was a moderate predictor of drug use severity at follow-up. Conclusions. The BDI measures a construct that is both stable and of predictive validity in a sample of non-abstinent Opiate Agonist maintenance patients, although very severe drug use at baseline appeared to reduce the stability of the BDI.
-
The Beck Depression Inventory in patients undergoing Opiate Agonist maintenance treatment.
The British journal of clinical psychology, 2006Co-Authors: Morten HesseAbstract:The Beck Depression Inventory (BDI) is a widely used measure of depression severity in both research and clinical contexts. This study aimed at assessing its stability and associations with ongoing drug use in a sample of patients in Opiate Agonist maintenance treatment who were not abstinent from illicit drugs. The study was a prospective, naturalistic study. Subjects in enhanced or standard psychosocial services along with Opiate Agonist maintenance treatment were administered the BDI and the European Addiction Severity Index (EuropASI) twice by research technicians, approximately 2 weeks after intake and at 18 months follow-up. There were rather small mean changes from intake to follow-up in the BDI, and mean-level stability in subjects was rather high as evidenced by a high intra-class correlation between intake score and follow-up score. The stability of the BDI was reduced at high levels of drug use severity at intake, and BDI was a moderate predictor of drug use severity at follow-up. The BDI measures a construct that is both stable and of predictive validity in a sample of non-abstinent Opiate Agonist maintenance patients, although very severe drug use at baseline appeared to reduce the stability of the BDI.
E J Van Bockstaele - One of the best experts on this subject based on the ideXlab platform.
-
Opiate Agonist induced re distribution of wntless a mu opioid receptor interacting protein in rat striatal neurons
Experimental Neurology, 2012Co-Authors: Beverly A S Reyes, Kunal Vakharia, Thomas N Ferraro, Robert Levenson, Wade H Berrettini, E J Van BockstaeleAbstract:Abstract Wntless (WLS), a mu-opioid receptor (MOR) interacting protein, mediates Wnt protein secretion that is critical for neuronal development. We investigated whether MOR Agonists induce re-distribution of WLS within rat striatal neurons. Adult male rats received either saline, morphine or [ d -Ala2, N-Me-Phe4, Gly-ol5]-enkephalin (DAMGO) directly into the lateral ventricles. Following thirty minutes, brains were extracted and tissue sections were processed for immunogold silver detection of WLS. In saline-treated rats, WLS was distributed along the plasma membrane and within the cytoplasmic compartment of striatal dendrites as previously described. The ratio of cytoplasmic to total dendritic WLS labeling was 0.70 ± 0.03 in saline-treated striatal tissue. Morphine treatment decreased this ratio to 0.48 ± 0.03 indicating a shift of WLS from the intracellular compartment to the plasma membrane. However, following DAMGO treatment, the ratio was 0.85 ± 0.05 indicating a greater distribution of WLS intracellularly. The difference in the re-distribution of the WLS following different Agonist exposure may be related to DAMGO's well known ability to induce internalization of MOR in contrast to morphine, which is less effective in producing receptor internalization. Furthermore, these data are consistent with our hypothesis that MOR Agonists promote dimerization of WLS and MOR, thereby preventing WLS from mediating Wnt secretion. In summary, our findings indicate differential Agonist-induced trafficking of WLS in striatal neurons following distinct Agonist exposure. Adaptations in WLS trafficking may represent a novel pharmacological target in the treatment of Opiate addiction and/or pain.
Dipak K. Sarkar - One of the best experts on this subject based on the ideXlab platform.
-
A combined Opiate Agonist and antAgonist treatment reduces prolactin secreting pituitary tumor growth
Journal of Cell Communication and Signaling, 2017Co-Authors: George Maglakelidze, Olivia Wynne, Dipak K. SarkarAbstract:Prolactin secreting pituitary adenomas (prolactinomas) is the most common pituitary tumors in humans. Animal studies have identified aggressive prolactinoma development in fetal alcohol exposed rats. We have recently identified a combination treatment of a μ opioid receptor antAgonist naltrexone and a δ opioid receptor Agonist D-Ala2-,N-Me-Phe4,Gly-ol Enkephalin (DPDPE) increases innate immune function. In this study, we tested whether naltrexone and DPDPE combination therapy is useful to control pituitary tumor growth. Fetal alcohol exposed and control Fischer 344 female rats at 60 days of age were ovariectomized and received an estrogen implant to induce prolactinomas. Six weeks after the estrogen implant, these animals received treatments of naltrexone and DPDPE or saline. The growth of the pituitary tumor prior to and after opioidergic agent treatments was visualized using magnetic resonance imaging (MRI). At the end of the treatment, pituitary weights, plasma prolactin and splenic levels of cytotoxic factors were determined. Both imaging data and weight data indicated that the volume and the weight of the pituitary were increased more after estrogen treatment in animals exposed to fetal alcohol than control. Naltrexone and DPDPE treatment reduced the weight and volume of the pituitary gland and plasma levels of prolactin in both fetal alcohol exposed and control-fed animals. The treatment of opioidergic agents also increased the levels of cytotoxic factors in the spleen. These data provide a novel possibility in treating pituitary tumors using a combination therapy of naltrexone and DPDPE.