V1b Receptor Antagonist SSR149415 and Naltrexone Synergistically Decrease Excessive Alcohol Drinking in Male and Female Mice

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141424/1/acer13544.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141424/2/acer13544_am.pd

The discriminative effects of the κ-opioid hallucinogen salvinorin A in nonhuman primates: dissociation from classic hallucinogen effects

RATIONALE: The widely available hallucinogen salvinorin A is a unique example of a plant-derived compound selective for κ-opioid receptors and may produce effects distinct from those of other compounds with classic hallucinogenic or dissociative properties which are also abused in humans. OBJECTIVES: The objective of this study is to characterize the salvinorin A discriminative cue in nonhuman primates with high κ-receptor genetic homology to humans. METHODS: Adult rhesus monkeys (n=3) were trained to discriminate salvinorin A (0.015 mg/kg, s.c.) from vehicle, in a food-reinforced operant discrimination assay. Parallel studies, using unconditioned behavioral endpoints (facial relaxation and ptosis) also evaluated the κ-opioid receptor mediation of salvinorin A in vivo function. RESULTS: Monkeys trained to discriminate salvinorin A generalized structurally diverse, centrally penetrating κ-agonists (bremazocine, U69,593, and U50,488). By contrast, μ- and δ-opioid agonists (fentanyl and SNC80, respectively) were not generalized, nor were the serotonergic 5HT2 hallucinogen psilocybin or the dissociative N-methyl-D-aspartic acid antagonist, ketamine. The discriminative effects of salvinorin A were blocked by the opioid antagonist quadazocine (0.32 mg/kg), but not by the 5HT2 antagonist ketanserin (0.1 mg/kg). Consistent with these findings, salvinorin and κ-agonists (e.g., U69,593) produce effects in the unconditioned endpoints (e.g., ptosis), whereas psilocybin was inactive. Conclusions: These findings support the conclusion that the interoceptive/discriminative cue produced by salvinorin A is mediated by agonism at κ-receptors and is mechanistically distinct from that produced by a classic serotonergic hallucinogen

Involvement of dynorphin and kappa opioid receptor in yohimbine-induced reinstatement of heroin seeking in rats

This is the peer reviewed version of the following article: Zhou, Y., Leri, F., Grella, S. L., Aldrich, J. V. and Kreek, M. J. (2013), Involvement of dynorphin and kappa opioid receptor in yohimbine-induced reinstatement of heroin seeking in rats. Synapse, 67: 358–361. doi:10.1002/syn.21638, which has been published in final form at http://doi.org/10.1002/syn.21638. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Although kappa opioid receptor (KOP-r) antagonists are known to reduce reinstatement of cocaine, alcohol and nicotine seeking induced by a variety of stressors, the role of KOP-r in yohimbine-induced reinstatement of heroin seeking has not been investigated. Yohimbine, used as a stressor, increases the hypothalamic-pituitary-adrenal (HPA) hormones, causes anxiety and induces heroin craving in humans. The present experiments were undertaken to assess the effects of yohimbine on reinstatement of heroin seeking and associated changes in preprodynorphin (ppDyn) expression and HPA hormonal levels; and to determine whether these effects could be reduced by pretreatment with the selective KOP-r antagonist nor-binaltorphimine (nor-BNI). After heroin self-administration for 12 days (3h/day, 0.05 mg/kg/infusion, i.v.) and extinction for 8 days, reinstatement included the first baseline test after vehicle injection, the second test of yohimbineinduced reinstatement (1.25 mg/kg, i.p.), pretreatment with vehicle or nor-BNI (20 mg/kg, i.p.), the third baseline test after vehicle injection, and the final test of yohimbine-induced reinstatement. Immediately after the last test, several mesolimbic regions and plasma were collected for analyses of ppDyn and KOP-r mRNA levels and HPA hormones. Yohimbineinduced reinstatement was fully blocked by nor-BNI pretreatment. Furthermore, yohimbine elevated plasma HPA hormones, and this increase was blunted by nor-BNI. Finally, rats pretreated with yohimbine displayed increased ppDyn mRNA levels in the nucleus accumbens shell and central nucleus of the amygdala. These data suggest that the stress responsive ppDyn/KOP-r system is a critical component of the neural circuitry underlying the effect of yohimbine stress on heroin seeking behavior and HPA activity

Overlapping Dopaminergic Pathway Genetic Susceptibility to Heroin and Cocaine Addictions in African Americans

Drugs of abuse activate the mesolimbic dopaminergic pathway. Genetic variations in the dopaminergic system may contribute to drug addiction. Several processes are shared between cocaine and heroin addictions but some neurobiological mechanisms may be specific. This study examined the association of 98 single nucleotide polymorphisms in 13 dopamine-related genes with heroin addiction (OD) and/or cocaine addiction (CD) in a sample of 801 African Americans (315 subjects with OD +/- CD, 279 subjects with CD, and 207 controls). Single-marker analyses provided nominally significant evidence for associations of 24 SNPs) in DRD1, ANKK1/DRD2, DRD3, DRD5, DBH, DDC, COMT and CSNK1E. A DRD2 7-SNPs haplotype that includes SNPs rs1075650 and rs2283265, which were shown to alter D2S/D2L splicing, was indicated in both addictions. The Met allele of the functional COMT Val158Met was associated with protection from OD. None of the signals remained significant after correction for multiple testing. The study results are in accordance with the results of previous studies, including our report of association of DRD1 SNP rs5326 with OD. The findings suggest the presence of an overlap in genetic susceptibility for OD and CD, as well as shared and distinct susceptibility for OD in subjects of African and European descent

The Effects of Herkinorin, the First mu-Selective Ligand from a Salvinorin A-Derived Scaffold, in a Neuroendocrine Biomarker Assay in Nonhuman Primates

Herkinorin is the first μ-opioid receptor-selective ligand from the salvinorin A diterpenoid scaffold. Herkinorin has relative μ \u3e κ \u3e δ binding selectivity, and it can act as an agonist at both μ- and κ-receptors, in vitro. These studies were the first in vivo evaluation of the effects of herkinorin in nonhuman primates, using prolactin release, a neuroendocrine biomarker assay that is responsive to both μ- and κ-agonists, as well as to compounds with limited ability to cross the blood-brain barrier. In cumulative dosing studies (0.01–0.32 mg/kg i.v.), herkinorin produced only small effects in gonadally intact males (n = 4), but a more robust effect in females (n = 4). Time course studies with herkinorin (0.32 mg/kg) confirmed this greater effectiveness in females and revealed a fast onset after i.v. administration (e.g., by 5–15 min). Antagonism experiments with different doses of nalmefene (0.01 and 0.1 mg/kg) caused dose-dependent and complete prevention of the effect of herkinorin in females. This is consistent with a principal μ-agonist effect of herkinorin, with likely partial contribution by κ-agonist effects. The peripherally selective antagonist quaternary naltrexone (1 mg/kg s.c.) caused approximately 70% reduction in the peak effect of herkinorin (0.32 mg/kg) in females, indicating that this effect of herkinorin is prominently mediated outside the blood-brain barrier

Characterization of Pyrrolidinyl-hexahydro-pyranopiperazines as a Novel Kappa Opioid Receptor Agonist Scaffold

The kappa agonist structure–activity relationship around the novel, pyrrolidinyl substituted pyranopiperazine scaffold was developed. More specifically, the dichloroPhenylAcetamide-Pyrrolidinyl-PyranoPiperazine (PAPPP) core A was the focus of our work. The modulation of kappa receptor potency/G-protein activation and arrestin recruitment with respect to changes of the piperazine R group in A was demonstrated. Reduced β2-arrestin recruitment and differential G-protein bias were observed for select analogues. To better understand the subtlety in receptor signaling, analogues were profiled as the resolved enantiomers. To determine in vivo target engagement, a subset of compounds was tested in mice for stimulation of serum prolactin, a neuroendocrine biomarker of KOR-agonist effects. Additional in vivo characterization included measurement of potential unwanted effects of kappa receptor activation such as sedation. These studies demonstrate a novel kappa receptor agonist scaffold with potential for G-protein signaling bias to probe in vivo pharmacology

Non-medical Cannabis Self-Exposure as a Dimensional Predictor of Opioid Dependence Diagnosis: A Propensity Score Matched Analysis

Background: The impact of increasing non-medical cannabis use on vulnerability to develop opioid use disorders has received considerable attention, with contrasting findings. A dimensional analysis of self-exposure to cannabis and other drugs, in individuals with and without opioid dependence (OD) diagnoses, may clarify this issue.Objective: To examine the age of onset of maximal self-exposure to cannabis, alcohol, cocaine, and heroin, in volunteers diagnosed with OD, using a rapidly administered instrument (the KMSK scales). To then determine whether maximal self-exposure to cannabis, alcohol, and cocaine is a dimensional predictor of odds of OD diagnoses.Methods: This outpatient observational study examined maximal self-exposure to these drugs, in volunteers diagnosed with DSM-IV OD or other drug diagnoses, and normal volunteers. In order to focus more directly on opioid dependence diagnosis as the outcome, volunteers who had cocaine dependence diagnoses were excluded. Male and female adults of diverse ethnicity were consecutively ascertained from the community, and from local drug treatment programs, in 2002–2013 (n = 574, of whom n = 94 had OD diagnoses). The age of onset of maximal self-exposure of these drugs was examined. After propensity score matching for age at ascertainment, gender, and ethnicity, a multiple logistic regression examined how increasing self-exposure to non-medical cannabis, alcohol and cocaine affected odds of OD diagnoses.Results: Volunteers with OD diagnoses had the onset of heaviest use of cannabis in the approximate transition between adolescence and adulthood (mean age = 18.9 years), and onset of heaviest use of alcohol soon thereafter (mean age = 20.1 years). Onset of heaviest use of heroin and cocaine was detected later in the lifespan (mean ages = 24.7 and 25.3 years, respectively). After propensity score matching for demographic variables, we found that the maximal self-exposure to cannabis and cocaine, but not to alcohol, was greater in volunteers with OD diagnoses, than in those without this diagnosis. Also, a multiple logistic regression detected that increasing self-exposure to cannabis and cocaine, but not alcohol, was a positive predictor of OD diagnosis.Conclusions/Importance: Increasing self-exposure to non-medical cannabis, as measured with a rapid dimensional instrument, was a predictor of greater odds of opioid dependence diagnosis, in propensity score-matched samples

Design, Synthesis, and Preliminary Evaluation of a Potential Synthetic Opioid Rescue Agent

BACKGROUND: One of the most prominent opioid analgesics in the United States is the high potency agonist fentanyl. It is used in the treatment of acute and chronic pain and as an anesthetic adjuvant. When used inappropriately, however, ingestion of just a few milligrams of fentanyl or other synthetic opioid can cause opioid-induced respiratory depression (OIRD), often leading to death. Currently, the treatment of choice for OIRD is the opioid receptor antagonist naloxone. Recent reports, however, suggest that higher doses or repeated dosing of naloxone (due to recurrence of respiratory depression) may be required to reverse fully fentanyl-induced respiratory depression, rendering this treatment inadequate. To combat this synthetic opioid overdose crisis, this research aims at identifying a novel opioid reversal agent with enhanced efficacy towards fentanyl and other synthetic opioids. METHODS: A series of naltrexone analogues were characterized for their ability to antagonize the effects of fentanyl in vitro utilizing a modified forskolin-induced cAMP accumulation assay. Lead analogue 29 was chosen to undergo further PK studies, followed by in vivo pharmacological analysis to determine its ability to antagonize opioid-induced antinociception in the hot plate assay. RESULTS: A series of potent MOR antagonists were identified, including the highly potent analogue 29 (IC50 = 2.06 nM). Follow-up PK studies revealed 29 to possess near 100% bioavailability following IP administration. Brain concentrations of 29 surpassed plasma concentrations, with an apparent terminal half-life of ~ 80 min in mice. In the hot plate assay, 29 dose-dependently (0.01–0.1 mg/kg; IP) and fully antagonized the antinociception induced by oxycodone (5.6 mg/kg; IP). Furthermore, the dose of 29 that is fully effective in preventing oxycodone-induced antinociception (0.1 mg/kg) was ineffective against locomotor deficits caused by the KOR agonist U50,488. CONCLUSIONS: Methods have been developed that have utility to identify enhanced rescue agents for the treatment of OIRD. Analogue 29, possessing potent MOR antagonist activity in vitro and in vivo, provides a promising lead in our search for an enhanced synthetic opioid rescue agent

LC-MS/MS quantification of salvinorin A from biological fluids

A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided completely by simply diluting each sample to 10 % (v/v) acetonitrile, 1 % (v/v) formic acid and injecting under high aqueous conditions for analyte focusing. Extensive plasma sample preparation was investigated including protein precipitation, SPE column selection, and plasma particulate removal. Human plasma samples were centrifuged at 21,000 × gravity for 4 minutes to obtain clear particulate-free plasma, from which 300 μl was spiked with internal standard and loaded onto a C18 SPE column with a 100 mg mL−1 loading capacity. Guard columns (C18, hand packed 1 mm × 20 mm) were exchanged after backpressure increased above 4600psi, about 250 injections. A shallow acetonitrile/water gradient was used, 29 to 33% CH3CN over 8 minutes to elute salvinorin A. Reduction of chemical noise was achieved using tandem mass spectrometry with multiple reaction monitoring while sensitivity increases were observed using a 50 μL injection volume onto a small bore analytical column (C18, 1 mm ID × 50 mm) thus increasing peak concentration. Limits of quantification were found to be 0.0125 ng mL−1 (CSF) and 0.05 ng mL−1 (plasma) with interday precision and accuracy below 1.7 % and 9.42 % (CSF) and 3.47 % and 12.37 % (plasma) respectively. This method was used to determine the concentration of salvinorin A from an in vivo Rhesus monkey study and a trial of healthy human research participants, using behaviorally active doses