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McElhinny CJ, Lewin AH, Mascarella SW, Runyon S, Brieaddy L, Carroll FI. Hydrolytic instability of the important orexin 1 receptor antagonist SB-334867: possible confounding effects on in vivo and in vitro studies. Bioorg Med Chem Lett 2012; 22:6661-4. [PMID: 23031594 DOI: 10.1016/j.bmcl.2012.08.109] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/13/2012] [Accepted: 08/28/2012] [Indexed: 01/05/2023]
Abstract
SB-334867 has been an important ligand for the study of the orexin 1 (OX1) receptor due to its high OX1/OX2 selectivity and bioavailability. This ligand however, contains a 2-methylbenzoxazole ring system which is known to undergo hydrolysis, particularly under acidic or basic conditions. The possibility that SB-334867 would be susceptible to significant hydrolysis was evaluated in various formulations and in the solid state. SB-334867 was found to be unstable under conditions commonly employed to prepare stock solutions for in vitro and in vivo studies. In addition, and most alarmingly, the hydrochloride salt of SB-334867 was found to quantitatively decompose to an OX1-inactive product even in the solid state. These findings combine to suggest that studies using SB-334867 (and any other 2-methylbenzoxazole-containing compound) should be performed with great care to avoid the confounding effects of the rapid hydrolytic decomposition of this susceptible structure.
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Schulze DR, Carroll FI, McMahon LR. Interactions between dopamine transporter and cannabinoid receptor ligands in rhesus monkeys. Psychopharmacology (Berl) 2012; 222:425-38. [PMID: 22374253 PMCID: PMC3620032 DOI: 10.1007/s00213-012-2661-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 02/02/2012] [Indexed: 11/28/2022]
Abstract
RATIONALE Δ(9)-tetrahydrocannabinol (Δ(9)-THC) modifies dopamine efflux. However, the extent to which cannabinoid and dopamine drugs modify each other's behavioral effects has not been fully established. OBJECTIVES This study examined dopamine releasers and/or transport inhibitors alone and in combination with cannabinoids in two drug discrimination assays. METHODS Experimentally and pharmacologically experienced rhesus monkeys (n = 5) discriminated Δ(9)-THC (0.1 mg/kg i.v.) from vehicle while responding under a fixed ratio 5 schedule of stimulus-shock termination. A separate group (n = 6) of monkeys responded under the same schedule, received daily Δ(9)-THC (1 mg/kg/12 h s.c.), and discriminated the cannabinoid antagonist rimonabant (1 mg/kg i.v.), i.e., cannabinoid withdrawal, from vehicle. A sign of withdrawal sign (head shaking) was examined in monkeys receiving Δ(9)-THC daily. RESULTS Rimonabant antagonized the Δ(9)-THC discriminative stimulus and a dose of Δ(9)-THC greater than the daily treatment attenuated the rimonabant discriminative stimulus. In monkeys discriminating Δ(9)-THC, the dopamine transporter ligands cocaine, amphetamine, bupropion, RTI 113, and RTI 177 produced a maximum of 2% responding on the drug lever and blocked the discriminative stimulus effects of Δ(9)-THC. In Δ(9)-THC treated monkeys discriminating rimonabant, the dopamine transporter ligands partially substituted for and increased the potency of rimonabant to produce discriminative stimulus effects. The dopamine antagonist haloperidol enhanced the Δ(9)-THC discriminative stimulus without significantly modifying the rimonabant discriminative stimulus. Imipramine and desipramine, which have low affinity for dopamine transporters, were less effective in modifying either the Δ(9)-THC or rimonabant discriminations. The dopamine transporter ligands and haloperidol attenuated head shaking, whereas imipramine and desipramine did not. CONCLUSIONS Dopamine release and/or inhibition of dopamine transport blocks detection of Δ(9)-THC and is potentially the mechanism by which some therapeutics (e.g., bupropion) reduce the subjective effects of marijuana and enhance the subjective effects of marijuana withdrawal.
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Ondachi P, Castro A, Luetje CW, Damaj MI, Mascarella SW, Navarro HA, Carroll FI. Synthesis and nicotinic acetylcholine receptor in vitro and in vivo pharmacological properties of 2'-fluoro-3'-(substituted phenyl)deschloroepibatidine analogues of 2'-fluoro-3'-(4-nitrophenyl)deschloroepibatidine. J Med Chem 2012; 55:6512-22. [PMID: 22742586 DOI: 10.1021/jm300575y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we report the synthesis and nicotinic acetylcholine receptor (nAChR) in vitro and in vivo pharmacological properties of 2'-fluoro-3'-(substituted phenyl)deschloroepibatidines 5b-g, analogues of 3'-(4-nitrophenyl) compound 5a. All compounds had high affinity for α4β2-nAChR and low affinity for α7-nAChR. Initial electrophysiological studies showed that all analogues were antagonists at α4β2-, α3β4-, and α7-nAChRs. The 4-carbamoylphenyl analogue 5g was highly selective for α4β2-nAChR over α3β4- and α7-nAChRs. All the analogues were antagonists of nicotine-induced antinociception in the tail-flick test. Molecular modeling docking studies using the agonist-bound form of the X-ray crystal structure of the acetylcholine binding protein suggested several different binding modes for epibatidine, varenicline, and 5a-g. In particular, a unique binding mode for 5g was suggested by these docking simulations. The high binding affinity, in vitro efficacy, and selectivity of 5g for α4β2-nAChR combined with its nAChR functional antagonist properties suggest that 5g will be a valuable pharmacological tool for studying the nAChR and may have potential as a pharmacotherapy for addiction and other central nervous system disorders.
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Roche MJ, Madren SM, Tallent CR, Carroll FI, Seltzman HH. Mild acetal cleavage using B-chlorocatecholborane in the synthesis of rearrangement-sensitive 2-arachidonoylglycerol. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.04.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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AlSharari SD, Carroll FI, McIntosh JM, Damaj MI. The antinociceptive effects of nicotinic partial agonists varenicline and sazetidine-A in murine acute and tonic pain models. J Pharmacol Exp Ther 2012; 342:742-9. [PMID: 22678099 DOI: 10.1124/jpet.112.194506] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotinic agonists display a wide-range profile of antinociceptive activity in acute, tonic, and chronic pain models. However, their effectiveness is limited by their unacceptable side effects. We investigated the antinociceptive effects of two new α4β2* nicotinic partial agonists, varenicline and sazetidine-A, in acute thermal and tonic pain mouse models. Both drugs failed to induce significant effects in the tail-flick and hot-plate tests after subcutaneous administration. However, they blocked nicotine's effects in these tests at very low doses. In contrast to acute pain tests, varenicline and sazetidine-A dose-dependently induced an analgesic effect in the mouse formalin test after systemic administration. Their antinociceptive effects were mediated, however, by different nicotinic acetylcholine receptor (nAChR) subtypes. Sazetidine-A effects were mediated by β2* nAChR subtypes, whereas varenicline actions were attributed to α3β4 nAChRs. Moreover, low inactive doses of varenicline blocked nicotine's actions in phase II of the formalin test. Overall, our results suggest that the antagonistic actions of varenicline at low doses are mediated by β2*-nAChRs and at higher doses as an agonist by α3β4*-nAChRs. In contrast, both actions of sazetidine-A are mediated by β2*-nAChR subtypes. These results suggest that nicotinic partial agonists possess analgesic effects in a rodent tonic pain model and may provide a potential treatment for the treatment of chronic pain disorders.
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Munro TA, Berry LM, Van't Veer A, Béguin C, Carroll FI, Zhao Z, Carlezon WA, Cohen BM. Long-acting κ opioid antagonists nor-BNI, GNTI and JDTic: pharmacokinetics in mice and lipophilicity. BMC Pharmacol 2012; 12:5. [PMID: 22642416 PMCID: PMC3411462 DOI: 10.1186/1471-2210-12-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/29/2012] [Indexed: 01/16/2023] Open
Abstract
Background Nor-BNI, GNTI and JDTic induce κ opioid antagonism that is delayed by hours and can persist for months. Other effects are transient. It has been proposed that these drugs may be slowly absorbed or distributed, and may dissolve in cell membranes, thus slowing elimination and prolonging their effects. Recent evidence suggests, instead, that they induce prolonged desensitization of the κ opioid receptor. Methods To evaluate these hypotheses, we measured relevant physicochemical properties of nor-BNI, GNTI and JDTic, and the timecourse of brain and plasma concentrations in mice after intraperitoneal administration (using LC-MS-MS). Results In each case, plasma levels were maximal within 30 min and declined by >80% within four hours, correlating well with previously reported transient effects. A strong negative correlation was observed between plasma levels and the delayed, prolonged timecourse of κ antagonism. Brain levels of nor-BNI and JDTic peaked within 30 min, but while nor-BNI was largely eliminated within hours, JDTic declined gradually over a week. Brain uptake of GNTI was too low to measure accurately, and higher doses proved lethal. None of the drugs were highly lipophilic, showing high water solubility (> 45 mM) and low distribution into octanol (log D7.4 < 2). Brain homogenate binding was within the range of many shorter-acting drugs (>7% unbound). JDTic showed P-gp-mediated efflux; nor- BNI and GNTI did not, but their low unbound brain uptake suggests efflux by another mechanism. Conclusions The negative plasma concentration-effect relationship we observed is difficult to reconcile with simple competitive antagonism, but is consistent with desensitization. The very slow elimination of JDTic from brain is surprising given that it undergoes active efflux, has modest affinity for homogenate, and has a shorter duration of action than nor-BNI under these conditions. We propose that this persistence may result from entrapment in cellular compartments such as lysosomes.
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Schank JR, Goldstein AL, Rowe KE, King CE, Marusich JA, Wiley JL, Carroll FI, Thorsell A, Heilig M. The kappa opioid receptor antagonist JDTic attenuates alcohol seeking and withdrawal anxiety. Addict Biol 2012; 17:634-47. [PMID: 22515275 DOI: 10.1111/j.1369-1600.2012.00455.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of kappa-opioid receptors (KOR) in the regulation of alcohol-related behaviors is not completely understood. For example, alcohol consumption has been reported to increase following treatment with KOR antagonists in rats, but was decreased in mice with genetic deletion of KOR. Recent studies have further suggested that KOR antagonists may selectively decrease alcohol self-administration in rats following a history of dependence. We assessed the effects of the KOR antagonist JDTic on alcohol self-administration, reinstatement of alcohol seeking induced by alcohol-associated cues or stress, and acute alcohol withdrawal-induced anxiety ('hangover anxiety'). JDTic dose-dependently reversed hangover anxiety when given 48 hours prior to testing, a time interval corresponding to the previously demonstrated anxiolytic efficacy of this drug. In contrast, JDTic decreased alcohol self-administration and cue-induced reinstatement of alcohol seeking when administered 2 hours prior to testing, but not at longer pre-treatment times. For comparison, we determined that the prototypical KOR antagonist nor-binaltorphimine can suppress self-administration of alcohol at 2 hours pre-treatment time, mimicking our observations with JDTic. The effects of JDTic were behaviorally specific, as it had no effect on stress-induced reinstatement of alcohol seeking, self-administration of sucrose, or locomotor activity. Further, we demonstrate that at a 2 hours pre-treatment time JDTic antagonized the antinociceptive effects of the KOR agonist U50,488H but had no effect on morphine-induced behaviors. Our results provide additional evidence for the involvement of KOR in regulation of alcohol-related behaviors and provide support for KOR antagonists, including JDTic, to be evaluated as medications for alcoholism.
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Jutkiewicz EM, Carroll FI, Woods JH. The behavioral and cardiovascular effects of nicotinic ligands designed from the epibatidine template. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1043.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rodriguez J, Cunningham C, Carroll FI, McMahon LR. Antagonism of the hypothermic effects of nicotinic receptor ligands in mice. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1048.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Andersen ML, Sawyer EK, Carroll FI, Howell LL. Influence of chronic dopamine transporter inhibition by RTI-336 on motor behavior, sleep, and hormone levels in rhesus monkeys. Exp Clin Psychopharmacol 2012; 20:77-83. [PMID: 22023668 PMCID: PMC3302935 DOI: 10.1037/a0026034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dopamine transporter (DAT) inhibitors have been developed as a promising treatment approach for cocaine dependence. However, the stimulant effects of DAT inhibitors have the potential to disrupt sleep patterns, and the influence of long-term treatment on dopamine neurochemistry is still unknown. The objectives of this study were to (1) explore the stimulant-related effects of chronic DAT inhibitor (RTI-336) treatment on motor activity and sleep-like measures in male rhesus monkeys (Macaca mulatta; n = 4) and (2) to determine the effect of drug treatment on prolactin and cortisol levels. Subjects were fitted with a collar-mounted activity monitor to evaluate their motor activity, with 4 days of baseline recording preceding 21 days of daily saline or RTI-336 (1 mg/kg/day; intramuscular) injections. Blood samples were collected immediately prior to and following chronic treatment to assess hormone levels. RTI-336 produced a significant increase in locomotor activity at the end of the daytime period compared to saline administration. During the 3-week treatment period, sleep efficiency was decreased and the fragmentation index and latency to sleep onset were significantly increased. Hormone levels were not changed throughout the study. Chronic treatment with RTI-336 has a mild but significant stimulant effect, as evidenced by the significant increase in activity during the evening period which may cause minor disruptions in sleep measures.
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Wu H, Wacker D, Mileni M, Katritch V, Han GW, Vardy E, Liu W, Thompson AA, Huang XP, Carroll FI, Mascarella SW, Westkaemper RB, Mosier PD, Roth BL, Cherezov V, Stevens RC. Structure of the human κ-opioid receptor in complex with JDTic. Nature 2012; 485:327-32. [PMID: 22437504 PMCID: PMC3356457 DOI: 10.1038/nature10939] [Citation(s) in RCA: 704] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 02/10/2012] [Indexed: 12/22/2022]
Abstract
Opioid receptors (ORs) mediate the actions of endogenous and exogenous opioids for many essential physiological processes including regulation of pain, respiratory drive, mood, and, in the case of κ-opioid receptors (KOR), dysphoria and psychotomimesis. Here we report the crystal structure of the human KOR (hKOR) in complex with the selective antagonist JDTic, arranged in parallel-dimers, at 2.9 angstrom resolution. The structure reveals important features of the ligand binding pocket that contribute to JDTic’s high affinity and subtype-selectivity for hKOR. Modeling of other important KOR-selective ligands, including the morphinan-derived antagonists nor-BNI and GNTI, and the diterpene agonist salvinorin A analog RB-64, reveals both common and distinct features for binding these diverse chemotypes. Analysis of site-directed mutagenesis and ligand structure-activity relationships confirms the interactions observed in the crystal structure, thereby providing a molecular explanation for hKOR subtype-selectivity along with insight essential for the design of hKOR compounds with new pharmacological properties.
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Kimmel HL, Nye JA, Voll R, Mun J, Stehouwer J, Goodman MM, Votaw JR, Carroll FI, Howell LL. Simultaneous measurement of extracellular dopamine and dopamine transporter occupancy by cocaine analogs in squirrel monkeys. Synapse 2012; 66:501-8. [PMID: 22237864 DOI: 10.1002/syn.21536] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 12/31/2011] [Indexed: 11/09/2022]
Abstract
Several classes of drugs bind to the dopamine transporter (DAT) with high affinity, but some are weaker positive reinforcers than cocaine, suggesting that affinity for and occupancy of the DAT is not the only determinant of a drug's reinforcing effectiveness. Other factors such as the rate of onset have been positively and strongly correlated with the reinforcing effects of DAT inhibitors in nonhuman primates. In the current studies, we examined the effects of acute systemic administration of cocaine and three cocaine analogs (RTI-150, RTI-177, and RTI-366) on binding to DAT in squirrel monkey brain using positron emission tomography (PET) neuroimaging. During the PET scan, we also measured drug effects on dopamine (DA) levels in the caudate using in vivo microdialysis. In general, our results suggest a lack of concordance between drug occupancy at DAT and changes in DA levels. These studies also indicate that acute cocaine administration decreases the availability of plasma membrane DAT for binding, even after cocaine is no longer blocking DA uptake as evidence by a return to basal DA levels.
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Gichinga MG, Olson JP, Butala E, Navarro HA, Gilmour BP, Mascarella SW, Carroll FI. Synthesis and Evaluation of Metabotropic Glutamate Receptor Subtype 5 Antagonists Based on Fenobam(). ACS Med Chem Lett 2011; 2:882-884. [PMID: 22523618 DOI: 10.1021/ml200162f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
In an effort to discover potent and selective metabotropic glutamate receptor subtype 5 (mGluR5) antagonists, 15 tetrahydropyrimidinone analogues of 1-(3-chlorophenyl)-3-(1-methyl-4-oxo-4,5-dihydro-1H-imidazol-2-yl)-urea (fenobam) were synthesized. These compounds were evaluated for antagonism of glutamate-mediated mobilization of internal calcium in an mGluR5 in vitro efficacy assay. The IC(50) value for 1-(3-chlorophenyl)-3-(1-methyl-4-oxo-1,4,5,6-tetrahydropyridine)urea (4g) was essentially identical to that of fenobam.
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Carroll FI, Lewin AH, Mascarella SW, Seltzman HH, Reddy PA. Designer drugs: a medicinal chemistry perspective. Ann N Y Acad Sci 2011; 1248:18-38. [DOI: 10.1111/j.1749-6632.2011.06199.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bergstrom BP, Sanberg SG, Andersson M, Mithyantha J, Carroll FI, Garris PA. Functional reorganization of the presynaptic dopaminergic terminal in parkinsonism. Neuroscience 2011; 193:310-22. [PMID: 21787843 PMCID: PMC3171576 DOI: 10.1016/j.neuroscience.2011.07.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 11/20/2022]
Abstract
Whether dopamine (DA) release is compensated during the presymptomatic phase of Parkinson's disease (PD) is controversial. Here we use in vivo voltammetry in the parkinsonian rat and an electrical stimulation protocol established to fatigue nigrostriatal dopaminergic (DAergic) neurons to investigate the plasticity of DA-release mechanisms. Amplitudes of evoked voltammetric signals recorded in intact rat striata decreased with repetitive, high-frequency stimulation (60 Hz, every 5 min/60 min). Strikingly, DA levels were maintained during an identical "fatiguing" protocol in 6-hydroxydopamine-lesioned (<40% denervation) striata in the absence of enhanced DA synthesis. In contrast, more severely lesioned striata (>55% denervation) also appeared to sustain DA release, however, this was demonstrated in the presence of enhanced synthesis. Sustained release was replicated in intact animals after irreversible blockade of the dopamine transporter (DAT) via RTI-76, implicating neuronal uptake as a trigger. We further demonstrate through kinetic analysis that lesions and compromised uptake target a "long-term" (time constant of minutes) presynaptic depression, which underlies the maintenance of release. Taken together, our findings identify a denervation-induced maintenance of DA release that was independent of activated synthesis and driven by altered uptake. This novel neuroadaptation may contribute to early preclinical normalization of function and help resolve discrepant findings regarding compensatory changes in DA release during progression of the parkinsonian state.
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Knoll AT, Muschamp JW, Sillivan SE, Ferguson D, Dietz DM, Meloni EG, Carroll FI, Nestler EJ, Konradi C, Carlezon WA. Kappa opioid receptor signaling in the basolateral amygdala regulates conditioned fear and anxiety in rats. Biol Psychiatry 2011; 70:425-33. [PMID: 21531393 PMCID: PMC3150294 DOI: 10.1016/j.biopsych.2011.03.017] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/07/2011] [Accepted: 03/10/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND The kappa opioid receptor (KOR) system contributes to the prodepressive and aversive consequences of stress and is implicated in the facilitation of conditioned fear and anxiety in rodents. Here, we sought to identify neural circuits that mediate KOR system effects on fear and anxiety in rats. METHODS We assessed whether fear conditioning induces plasticity in KOR or dynorphin (the endogenous KOR ligand) messenger RNA (mRNA) expression in the basolateral (BLA) and central (CeA) nuclei of the amygdala, hippocampus, or striatum. We then assessed whether microinfusions of the KOR antagonist JDTic (0-10 μg/side) into the BLA or CeA affect the expression of conditioned fear or anxiety. Finally, we examined whether fear extinction induces plasticity in KOR mRNA expression that relates to the quality of fear extinction. RESULTS Fear conditioning upregulated KOR mRNA in the BLA by 65% and downregulated it in the striatum by 22%, without affecting KOR levels in the CeA or hippocampus, or dynorphin levels in any region. KOR antagonism in either the BLA or CeA decreased conditioned fear in the fear-potentiated startle paradigm, whereas KOR antagonism in the BLA, but not the CeA, produced anxiolytic-like effects in the elevated plus maze. Effective fear extinction was associated with a 67% reduction in KOR mRNA in the BLA. CONCLUSIONS These findings suggest that fear conditioning and extinction dynamically regulate KOR expression in the BLA and provide evidence that the BLA and CeA are important neural substrates mediating the anxiolytic-like effects of KOR antagonists in models of fear and anxiety.
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MESH Headings
- Amygdala/drug effects
- Amygdala/metabolism
- Animals
- Anxiety/metabolism
- Conditioning, Psychological/drug effects
- Conditioning, Psychological/physiology
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Disease Models, Animal
- Dynorphins/physiology
- Extinction, Psychological/physiology
- Fear/drug effects
- Fear/physiology
- Gene Expression Regulation/physiology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Male
- Maze Learning/drug effects
- Maze Learning/physiology
- Microinjections
- Piperidines/administration & dosage
- Piperidines/pharmacology
- Rats
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, kappa/biosynthesis
- Receptors, Opioid, kappa/physiology
- Reflex, Startle/drug effects
- Reflex, Startle/physiology
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Tetrahydroisoquinolines/administration & dosage
- Tetrahydroisoquinolines/pharmacology
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Melief EJ, Miyatake M, Carroll FI, Béguin C, Carlezon WA, Cohen BM, Grimwood S, Mitch CH, Rorick-Kehn L, Chavkin C. Duration of action of a broad range of selective κ-opioid receptor antagonists is positively correlated with c-Jun N-terminal kinase-1 activation. Mol Pharmacol 2011; 80:920-9. [PMID: 21832171 DOI: 10.1124/mol.111.074195] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The κ-opioid receptor is a widely expressed G-protein-coupled receptor that has been implicated in biological responses to pain, stress, anxiety, and depression, and its potential as a therapeutic target in these syndromes is becoming increasingly apparent. However, the prototypical selective κ-opioid antagonists have very long durations of action that have been attributed to c-Jun N-terminal kinase (JNK) 1 activation in vivo. To test generality of this proposed noncompetitive mechanism, we used C57BL/6 wild type mice to determine the durations of antagonist action of novel κ-opioid receptor ligands and examined their efficacies for JNK1 activation compared with conventional competitive antagonists. Of the 12 compounds tested, 5 had long durations of action that positively correlated with JNK activation: RTI-5989-97 [(3S)-7-hydroxy-N-[(1S)-1-[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl}-(2-methylpropyl]-2-methyl-1,2,3,4-tetrahydro-3-isoquinolinecarboxamide], RTI-5989-194 [(3R)-7-hydroxy-N-[(1S)-1-[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl}-(2-methylbutyl]-1,2,3,4-tetrahydro-3-isoquinolinecarboxamide], RTI-5989-241 [(3R)-7-hydroxy-N-[(1S)-1-{[(3R,4R)-4-(3-methoxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl}-2-methylpropyl]-1,2,3,4-tetrahydroisoquinoline-3-carboxamide)], nor-binaltorphimine (nor-BNI); and (3R)-7-hydroxy-N-((1S)-1-{[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl}-2-methylpropyl)-1,2,3,4-tetrahydro-3-isoquinolinecarboxamide (JDTic). Seven had short durations of action and did not increase phospho-JNK-ir: RTI-5989-212[(3R)-N-[(1S)-1-[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl}-(2-methylpropyl]-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxamide], RTI-5989-240 [(3R)-7-hydroxy-N-[(1S)-1-[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethylpiperidin-1-yl]methyl}-(2-methylpropyl]-3-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxamide], JSPA0658 [(S)-3-fluoro-4-(4-((2-(3,5-dimethylphenyl)pyrrolidin-1-yl)methyl)phenoxy)benzamide], JSPA071B [(S)-3-fluoro-4-(4-((2-(3,5-bis(trifluoromethyl)phenyl)pyrrolidin-1-yl)methyl)phenoxy)benzamide]. PF-4455242 [2-methyl-N-((2'-(pyrrolidin-1-ylsulfonyl)biphenyl-4-yl)methyl)propan-1-amine], PF-4455242 [2-methyl-N-((2'-(pyrrolidin-1-ylsulfonyl)biphenyl-4-yl)methyl)propan-1-amine], FP3FBZ [(S)-3-fluoro-4-(4-((2-(3-fluorophenyl)pyrrolidin-1-yl)methyl)phenoxy)benzamide], and naloxone. After long-acting antagonist treatment, pJNK-ir did not increase in mice lacking the κ-opioid receptor; increased pJNK-ir returned to baseline by 48 h after treatment; and a second challenge with nor-BNI 72 h after the first did not increase pJNK-ir. Long-lasting antagonism and increased phospho-JNK-ir were not seen in animals lacking the JNK1 isoform. These results support the hypothesis that the duration of action of small molecule κ-opioid receptor antagonists in vivo is determined by their efficacy in activating JNK1 and that persistent inactivation of the κ-receptor does not require sustained JNK activation.
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Gichinga MG, Olson JP, Butala E, Gilmour BP, Navarro HH, Carroll FI. Preparation of a Series of 5-Methyl-3-(substituted)-[1,2,4]triazines. Tetrahedron Lett 2011; 52:3345-3346. [PMID: 21779134 DOI: 10.1016/j.tetlet.2011.04.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Procedures for the synthesis of thirty-six 5-methyl-3-(substituted)-[1,2,4]triazines have been described. These compounds were evaluated for antagonism at metabotropic glutamate receptor subtype 5. Two compounds, 5b and 3c, were determined to be low micromolar inhibitors of mGluR5.
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94
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Carroll FI, Blough BE, Pidaparthi RR, Abraham P, Gong PK, Deng L, Huang X, Gunnell M, Lay JO, Peterson EC, Owens SM. Synthesis of mercapto-(+)-methamphetamine haptens and their use for obtaining improved epitope density on (+)-methamphetamine conjugate vaccines. J Med Chem 2011; 54:5221-8. [PMID: 21682289 DOI: 10.1021/jm2004943] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study reports the synthesis of the mercapto-hapten (S)-N-(2-(mercaptoethyl)-6-(3-(2-(methylamino)propyl)phenoxy)hexanamide [3, (+)-METH HSMO9] and its use to prepare METH-conjugated vaccines (MCV) from maleimide-activated proteins. MALDI-TOF mass spectrometry analysis of the MCV synthesized using 3 showed there was a high and controllable epitope density on two different carrier proteins. In addition, the MCV produced a substantially greater immunological response in mice than previous METH haptens, and a monoclonal antibody generated from this MCV in mice showed a very high affinity for (+)-METH (K(D) = 6.8 nM). The efficient covalent coupling of (+)-METH HSMO9 to the activated carrier proteins suggests that this approach could be cost-effective for large-scale production of MCV. In addition, the general methods described for the synthesis of (+)-METH HSMO9 (3) and its use to synthesize MCV will be applicable for conjugated vaccines of small molecules and other substances of abuse such as morphine, nicotine, and cocaine.
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Olson JP, Gichinga MG, Butala E, Navarro HA, Gilmour BP, Carroll FI. Synthesis and evaluation of 1,2,4-methyltriazines as mGluR5 antagonists. Org Biomol Chem 2011; 9:4276-86. [PMID: 21503289 DOI: 10.1039/c0ob01190h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In previous studies we showed that 3-(substituted phenylethynyl)-5-methyl[1,2,4]triazine analogues of MPEP were potent antagonists of glutamate-mediated mobilization of internal calcium in an mGluR5 in vitro efficacy assay. In the present study we report the synthesis and evaluation of six 3-(substituted biphenylethynyl)-5-methyl[1,2,4]triazines (5a-f), and five 3-(substituted phenoxyphenylethynyl)-5-methyltriazines (6a-e). Compound 2-(4-fluorophenyl-5-[2-(5-methyl[1,2,4]triazine-3-yl)ethynyl]benzonitrile (5f) with an IC(50) of 28.2 nM was the most potent analogue.
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Kimmel HL, Nye JA, Voll RJ, Stehouwer JS, Goodman MM, Votaw J, Carroll FI, Howell LL. Acute administration of cocaine decreases cell surface expression of DAT in the squirrel monkey caudate. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1083.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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97
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Kuntz CP, Lill MA, Carroll FI, Barker EL. Docking 3‐phenyltropane analogs into an ensemble of serotonin transporter homology model conformations. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1083.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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98
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Hill ER, Huang X, Zhan CG, Ivy Carroll F, Gu HH. Interaction of tyrosine 151 in norepinephrine transporter with the 2β group of cocaine analog RTI-113. Neuropharmacology 2011; 61:112-20. [PMID: 21420984 DOI: 10.1016/j.neuropharm.2011.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 03/10/2011] [Accepted: 03/12/2011] [Indexed: 12/27/2022]
Abstract
Cocaine binds and inhibits dopamine transporter (DAT), norepinephrine transporter (NET) and serotonin transporter. The residues forming cocaine binding sites are unknown. RTI-113, a cocaine analog, is 100× more potent at inhibiting DAT than inhibiting NET. Here we show that removing the hydroxyl group from residue Tyr151 in NET by replacing it with Phe, the corresponding residue in DAT, increased the sensitivity of NET to RTI-113, while the reverse mutation in DAT decreased the sensitivity of DAT to RTI-113. In contrast, RTI-31, another cocaine analog having the same structure as RTI-113 but with the phenyl group at the 2β position replaced by a methyl group, inhibits the transporter mutants equally well whether a hydroxyl group is present at the residue or not. The data suggest that this residue contributes to cocaine binding site and is close to the 2β position of cocaine analogs. These results are consistent with our previously proposed cocaine-DAT binding model where cocaine initially binds to a site that does not overlap with, but is close to, the dopamine-binding site. Computational modeling and molecular docking yielded a binding model that explains the observed changes in RTI-113 inhibition potencies.
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Carroll FI, Muresan AZ, Blough BE, Navarro HA, Mascarella SW, Eaton JB, Huang X, Damaj MI, Lukas RJ. Synthesis of 2-(substituted phenyl)-3,5,5-trimethylmorpholine analogues and their effects on monoamine uptake, nicotinic acetylcholine receptor function, and behavioral effects of nicotine. J Med Chem 2011; 54:1441-8. [PMID: 21319801 DOI: 10.1021/jm1014555] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Toward development of smoking cessation aids superior to bupropion (2), we describe synthesis of 2-(substituted phenyl)-3,5,5-trimethylmorpholine analogues 5a-5h and their effects on inhibition of dopamine, norepinephrine, and serotonin uptake, nicotinic acetylcholine receptor (nAChR) function, acute actions of nicotine, and nicotine-conditioned place preference (CPP). Several analogues encompassing aryl substitutions, N-alkylation, and alkyl extensions of the morpholine ring 3-methyl group provided analogues more potent in vitro than (S,S)-hydroxybupropion (4a) as inhibitors of dopamine or norepinephrine uptake and antagonists of nAChR function. All of the new (S,S)-5 analogues had better potency than (S,S)-4a as blockers of acute nicotine analgesia in the tail-flick test. Two analogues with highest potency at α3β4*-nAChR and among the most potent transporter inhibitors have better potency than (S,S)-4a in blocking nicotine-CPP. Collectively, these findings illuminate mechanisms of action of 2 analogues and identify deshydroxybupropion analogues 5a-5h as possibly superior candidates as aids to smoking cessation.
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George O, Lloyd A, Carroll FI, Damaj MI, Koob GF. Varenicline blocks nicotine intake in rats with extended access to nicotine self-administration. Psychopharmacology (Berl) 2011; 213:715-22. [PMID: 20924754 PMCID: PMC3033995 DOI: 10.1007/s00213-010-2024-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 09/16/2010] [Indexed: 01/22/2023]
Abstract
RATIONALE Much evidence indicates that individuals use tobacco primarily to experience the psychopharmacological properties of nicotine. Varenicline, a partial α4β2 nicotinic acetylcholine receptor (nAChR) agonist, is effective in reducing nicotine craving and relapse in smokers, suggesting that α4β2 nAChRs may play a key role in nicotine dependence. In rats, the effect of varenicline on nicotine intake has only been studied with limited access to the drug, a model of the positive reinforcing effect of nicotine. Varenicline has not been tested on the increase in motivation to take nicotine in nicotine-dependent rats. OBJECTIVES The present study evaluated the effects of varenicline on nicotine intake in rats with extended access to nicotine self-administration (23 h/day), a condition leading to the development of nicotine dependence. We hypothesized that varenicline's effects on nicotine self-administration would be greater in rats with extended than limited access to the drug and after forced abstinence rather than during baseline self-administration. RESULTS Varenicline dose-dependently decreased nicotine self-administration in rats with limited (1 h/day) and extended (23 h/day) access. Despite an increased sensitivity to the motivational effects of abstinence on nicotine intake compared with limited-access rats, varenicline was equally effective in decreasing nicotine intake in dependent rats with extended access to nicotine. CONCLUSION These results suggest that α4β2 nAChRs are critical in mediating the positive reinforcing effects of nicotine but may not be a key element underlying the negative reinforcement process responsible for the increased nicotine intake after abstinence in dependent subjects.
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