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Involvement of KOP-r in cocaine withdrawal-induced conditioned place aversion in rats
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Abstracts / Drug and Alcohol Dependence 140 (2014) e169–e251
Devices) cell lines stably expressing either the OX1 or OX2 receptor. Select compounds were assessed in a conditioned place preference assay. Results: A number of compounds showed low nanomolar potency at the OX1 receptor and excellent selectivity (>100-fold) over the OX2 receptor. Several structural features that are important for OX1 activity have been identified. For instance, as the size of substituents increases at the 7-position of the tetrahydroisoquinoline the OX1 potency also increases. When tested in vivo, a compound with good in vitro potency and OX1 selectivity alone did not have place conditioning effect but blocked the acquisition of conditioned place preference to methamphetamine in rats. Conclusions: Structure–activity relationship studies have resulted in several compounds that are potent and OX1 selective. One such compound showed promising effect against the rewarding effects of methamphetamine. These results will facilitate the development of potent and selective OX1 antagonists as medications for the treatment of drug addiction. Financial support: NIH grants DA032837 and DA026582. http://dx.doi.org/10.1016/j.drugalcdep.2014.02.690 Genotype diversity of HCV among MMT patients in Wuhan, China Sheng Zhou 2 , W. Zhou 1 , Richard S. Schottenfeld 3 , W. Kong 1 , M. Liu 3 , J. Peng 3 , P. Liu 3 , Marek C. Chawarski 3 1 Yale School of Medicine, New Haven, CT, United States 2 Huazhong University of Science & Technology, Wuhan, China 3 CDC, Wuhan, China
Aims: We previously found a high rate (555/1200, 46%) of HCV seroconversion following methadone maintenance treatment (MMT) entry and consequently set out to evaluate HCV genotype diversity and identify potential networks of HCV transmission among MMT patients in Wuhan. Methods: HCV RNA was extracted from blood specimens from a sample of 84 HCV seroconverters. The samples were analyzed using real-time PCR; HCV RNA was amplified by reverse-transcription PCR with primers targeting the 5 -untranslated and core region (5 UTR/Core) and then sequenced for computation of phylogenetic tree and genetic distance. Results: HCV seroconverters were 67% male, with a median age 39 years and median duration of drug use of 9.5 years; 64% had less than high school education; 80% reported a history of injection drug use (IDU). Genotype 3b was predominant (34, 41%) followed by 6a (30, 36%), 3a (9, 11%), 1b (9, 11%) and 1a (2, 2%). Genotype 6a was associated with age > 30 years (p < .05), and IDU was associated with higher HCV RNA concentration (5.7 × 106 vs 3.3 × 106 IU/ml, p < .01). Inspection of phylogenetic tree colorcoded by the patient’s clinic location indicated genotype clustering according to geographical location; genetic distances of 0.0 and homogeneity index > 98 were found for six 2-person cluster and one 3-person cluster of patients, with all patients in a cluster coming from the same clinic or district. Conclusions: Genotype 3 and 6 are most prevalent among MMT patients who seroconvert. Geographical clustering of cases with high genetic homogeneity suggests direct transmission of the virus among seroconverters, who may have continued illicit drug use following MMT admission. Further research is required to examine specific risks, behavioral factors, and transmission routes of
HCV among MMT patients in Wuhan to implement more effective prevention and treatment strategies. Financial support: CDC, Wuhan, China; NIDA DA026797 & CMHC/DMHAS/State of Connecticut. http://dx.doi.org/10.1016/j.drugalcdep.2014.02.691 Involvement of KOP-r in cocaine withdrawal-induced conditioned place aversion in rats Yan Zhou, Y. Litvin, D. Pfaff, M. Kreek Rockefeller University, New York, NY, United States Aims: Drug withdrawal-associated CPA is a test that is sensitive to the function of brain aversive systems and has been used to measure the expression of negative motivational symptoms of opiate withdrawal. However, CPA induced by cocaine withdrawal (CW) has not been established. Here we developed a paradigm of CW induced CPA (CW-CPA) and characterized this model with kappar opioid receptor (KOP-r) antagonist nor-BNI. We also tested social behavior in CW. Methods: Rats were exposed to chronic escalating-dose (3 × 15–30 mg/kg at 1-h intervals from day 1 to 14) or steady-dose (3 × 15 mg/kg/day for 14 days) “binge” cocaine administration. The conditioning phase began on day 10, 30 min before “binge” injections (20 h after the last “binge” cocaine), and lasted for 5 days to day 14. During CW conditioning, rats were randomly assigned and confined to one conditioning chamber for 30 min. In post–conditioning test, rats were allowed free access to both chambers for 30 min on CW day 1 to 3 (acute), day 14 (chronic) or day 28 (protracted). For social behavior, we used a social investigation paradigm and assessed spatial preference and anxiety-like behaviors relative to an unfamiliar large male conspecific (with plexiglass partition) during acute CW. Results: (1) Rats expressed the CW-CPA following CW from chronic “binge” escalating-dose, but not steady-dose, regimen; (2) the CW-CPA had an onset in acute CW, persisted into chronic CW, and returned to baseline after protracted CW; (3) pretreatment with nor-BNI in acute CW reversed the CW-CPA at 5 mg/kg, but not 1 mg/kg, dose. Naloxone (mu opioid receptor anatagonist, 1 mg/kg) had no effect; (4) nor-BNI blocked HPA activation in acute CW-CPA; (5) preprodynorphin mRNA levels were increased in the central amygdala by acute CW-CPA; (6) spatial preference or anxiety-like behavior was unaltered in acute CW. Conclusions: The involvement of KOP-r in the aversive stimulus effects of the CW-CPA provides validity for the use of place conditioning as a measure to study the cocaine withdrawal-related dysphoria. Social investigation model does not serve a reliable model for CW. Financial support: NIDA Center Grant DA-P60-05130 (MJK). http://dx.doi.org/10.1016/j.drugalcdep.2014.02.692 Effects of orexin receptor antagonism on methamphetamine-seeking in male and female adolescent and adult rats Natalie Zlebnik, Nathan Holtz, Marilyn E. Carroll Psychiatry, University of MN, Minneapolis, MN, United States Aims: Previous studies have shown enhanced vulnerability to addiction in adolescent (vs. adult) as well as female (vs. male) rats. The orexin system recently has been implicated in addiction and
Abstracts / Drug and Alcohol Dependence 140 (2014) e169–e251
Devices) cell lines stably expressing either the OX1 or OX2 receptor. Select compounds were assessed in a conditioned place preference assay. Results: A number of compounds showed low nanomolar potency at the OX1 receptor and excellent selectivity (>100-fold) over the OX2 receptor. Several structural features that are important for OX1 activity have been identified. For instance, as the size of substituents increases at the 7-position of the tetrahydroisoquinoline the OX1 potency also increases. When tested in vivo, a compound with good in vitro potency and OX1 selectivity alone did not have place conditioning effect but blocked the acquisition of conditioned place preference to methamphetamine in rats. Conclusions: Structure–activity relationship studies have resulted in several compounds that are potent and OX1 selective. One such compound showed promising effect against the rewarding effects of methamphetamine. These results will facilitate the development of potent and selective OX1 antagonists as medications for the treatment of drug addiction. Financial support: NIH grants DA032837 and DA026582. http://dx.doi.org/10.1016/j.drugalcdep.2014.02.690 Genotype diversity of HCV among MMT patients in Wuhan, China Sheng Zhou 2 , W. Zhou 1 , Richard S. Schottenfeld 3 , W. Kong 1 , M. Liu 3 , J. Peng 3 , P. Liu 3 , Marek C. Chawarski 3 1 Yale School of Medicine, New Haven, CT, United States 2 Huazhong University of Science & Technology, Wuhan, China 3 CDC, Wuhan, China
Aims: We previously found a high rate (555/1200, 46%) of HCV seroconversion following methadone maintenance treatment (MMT) entry and consequently set out to evaluate HCV genotype diversity and identify potential networks of HCV transmission among MMT patients in Wuhan. Methods: HCV RNA was extracted from blood specimens from a sample of 84 HCV seroconverters. The samples were analyzed using real-time PCR; HCV RNA was amplified by reverse-transcription PCR with primers targeting the 5 -untranslated and core region (5 UTR/Core) and then sequenced for computation of phylogenetic tree and genetic distance. Results: HCV seroconverters were 67% male, with a median age 39 years and median duration of drug use of 9.5 years; 64% had less than high school education; 80% reported a history of injection drug use (IDU). Genotype 3b was predominant (34, 41%) followed by 6a (30, 36%), 3a (9, 11%), 1b (9, 11%) and 1a (2, 2%). Genotype 6a was associated with age > 30 years (p < .05), and IDU was associated with higher HCV RNA concentration (5.7 × 106 vs 3.3 × 106 IU/ml, p < .01). Inspection of phylogenetic tree colorcoded by the patient’s clinic location indicated genotype clustering according to geographical location; genetic distances of 0.0 and homogeneity index > 98 were found for six 2-person cluster and one 3-person cluster of patients, with all patients in a cluster coming from the same clinic or district. Conclusions: Genotype 3 and 6 are most prevalent among MMT patients who seroconvert. Geographical clustering of cases with high genetic homogeneity suggests direct transmission of the virus among seroconverters, who may have continued illicit drug use following MMT admission. Further research is required to examine specific risks, behavioral factors, and transmission routes of
HCV among MMT patients in Wuhan to implement more effective prevention and treatment strategies. Financial support: CDC, Wuhan, China; NIDA DA026797 & CMHC/DMHAS/State of Connecticut. http://dx.doi.org/10.1016/j.drugalcdep.2014.02.691 Involvement of KOP-r in cocaine withdrawal-induced conditioned place aversion in rats Yan Zhou, Y. Litvin, D. Pfaff, M. Kreek Rockefeller University, New York, NY, United States Aims: Drug withdrawal-associated CPA is a test that is sensitive to the function of brain aversive systems and has been used to measure the expression of negative motivational symptoms of opiate withdrawal. However, CPA induced by cocaine withdrawal (CW) has not been established. Here we developed a paradigm of CW induced CPA (CW-CPA) and characterized this model with kappar opioid receptor (KOP-r) antagonist nor-BNI. We also tested social behavior in CW. Methods: Rats were exposed to chronic escalating-dose (3 × 15–30 mg/kg at 1-h intervals from day 1 to 14) or steady-dose (3 × 15 mg/kg/day for 14 days) “binge” cocaine administration. The conditioning phase began on day 10, 30 min before “binge” injections (20 h after the last “binge” cocaine), and lasted for 5 days to day 14. During CW conditioning, rats were randomly assigned and confined to one conditioning chamber for 30 min. In post–conditioning test, rats were allowed free access to both chambers for 30 min on CW day 1 to 3 (acute), day 14 (chronic) or day 28 (protracted). For social behavior, we used a social investigation paradigm and assessed spatial preference and anxiety-like behaviors relative to an unfamiliar large male conspecific (with plexiglass partition) during acute CW. Results: (1) Rats expressed the CW-CPA following CW from chronic “binge” escalating-dose, but not steady-dose, regimen; (2) the CW-CPA had an onset in acute CW, persisted into chronic CW, and returned to baseline after protracted CW; (3) pretreatment with nor-BNI in acute CW reversed the CW-CPA at 5 mg/kg, but not 1 mg/kg, dose. Naloxone (mu opioid receptor anatagonist, 1 mg/kg) had no effect; (4) nor-BNI blocked HPA activation in acute CW-CPA; (5) preprodynorphin mRNA levels were increased in the central amygdala by acute CW-CPA; (6) spatial preference or anxiety-like behavior was unaltered in acute CW. Conclusions: The involvement of KOP-r in the aversive stimulus effects of the CW-CPA provides validity for the use of place conditioning as a measure to study the cocaine withdrawal-related dysphoria. Social investigation model does not serve a reliable model for CW. Financial support: NIDA Center Grant DA-P60-05130 (MJK). http://dx.doi.org/10.1016/j.drugalcdep.2014.02.692 Effects of orexin receptor antagonism on methamphetamine-seeking in male and female adolescent and adult rats Natalie Zlebnik, Nathan Holtz, Marilyn E. Carroll Psychiatry, University of MN, Minneapolis, MN, United States Aims: Previous studies have shown enhanced vulnerability to addiction in adolescent (vs. adult) as well as female (vs. male) rats. The orexin system recently has been implicated in addiction and