Eliot L. Gardner, Ph.D.

@article{Song2012,

title = {YQA14: a novel dopamine D3 receptor antagonist that inhibits cocaine self-administration in rats and mice, but not in D3 receptor-knockout mice.},

author = {Rui Song and Ri-Fang Yang and Ning Wu and Rui-Bin Su and Jin Li and Xiao-Qing Peng and Xia Li and Jozsef Gaal and Zheng-Xiong Xi and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/21507153},

doi = {10.1111/j.1369-1600.2011.00317.x},

issn = {1369-1600 (Electronic); 1355-6215 (Linking)},

year  = {2012},

date = {2012-03-01},

journal = {Addict Biol},

volume = {17},

number = {2},

pages = {259--273},

address = {Beijing Institute of Pharmacology and Toxicology, Beijing, China.},

abstract = {The dopamine (DA) D3 receptor is posited to be importantly involved in drug reward and addiction, and D3 receptor antagonists have shown extraordinary promise as potential anti-addiction pharmacotherapeutic agents in animal models of drug addiction. SB-277011A is the best characterized D3 receptor antagonist in such models. However, the potential use of SB-277011A in humans is precluded by pharmacokinetic and toxicity problems. We here report a novel D3 receptor antagonist YQA14 that shows similar pharmacological properties as SB-277011A. In vitro receptor binding assays suggest that YQA14 has two binding sites on human cloned D3 receptors with K(i-High) (0.68 x 10(-4) nM) and K(i-Low) (2.11 nM), and displays > 150-fold selectivity for D3 over D2 receptors and > 1000-fold selectivity for D3 over other DA receptors. Systemic administration of YQA14 (6.25-25 mg/kg) or SB-277011A (12.5-25 mg/kg) significantly and dose-dependently reduced intravenous cocaine self-administration under both low fixed-ratio and progressive-ratio reinforcement conditions in rats, while failing to alter oral sucrose self-administration and locomotor activity, suggesting a selective inhibition of drug reward. However, when the drug dose was increased to 50 mg/kg, YQA14 and SB-277011A significantly inhibited basal and cocaine-enhanced locomotion in rats. Finally, both D3 antagonists dose-dependently inhibited intravenous cocaine self-administration in wild-type mice, but not in D3 receptor-knockout mice, suggesting that their action is mediated by D3 receptor blockade. These findings suggest that YQA14 has a similar anti-addiction profile as SB-277011A, and deserves further study and development.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Xi2011,

title = {Brain cannabinoid CB(2) receptors modulate cocaine's actions in mice.},

author = {Zheng-Xiong Xi and Xiao-Qing Peng and Xia Li and Rui Song and Hai-Ying Zhang and Qing-Rong Liu and Hong-Ju Yang and Guo-Hua Bi and Jie Li and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/21785434},

doi = {10.1038/nn.2874},

issn = {1546-1726 (Electronic); 1097-6256 (Linking)},

year  = {2011},

date = {2011-07-24},

journal = {Nat Neurosci},

volume = {14},

number = {9},

pages = {1160--1166},

address = {Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA. zxi@intra.nida.nih.gov},

abstract = {The presence and function of cannabinoid CB(2) receptors in the brain have been the subjects of much debate. We found that systemic, intranasal or intra-accumbens local administration of JWH133, a selective CB(2) receptor agonist, dose-dependently inhibited intravenous cocaine self-administration, cocaine-enhanced locomotion, and cocaine-enhanced accumbens extracellular dopamine in wild-type and CB(1) receptor knockout (CB(1)(-/-), also known as Cnr1(-/-)) mice, but not in CB(2)(-/-) (Cnr2(-/-)) mice. This inhibition was mimicked by GW405833, another CB(2) receptor agonist with a different chemical structure, and was blocked by AM630, a selective CB(2) receptor antagonist. Intra-accumbens administration of JWH133 alone dose-dependently decreased, whereas intra-accumbens administration of AM630 elevated, extracellular dopamine and locomotion in wild-type and CB(1)(-/-) mice, but not in CB(2)(-/-) mice. Intra-accumbens administration of AM630 also blocked the reduction in cocaine self-administration and extracellular dopamine produced by systemic administration of JWH133. These findings suggest that brain CB(2) receptors modulate cocaine's rewarding and locomotor-stimulating effects, likely by a dopamine-dependent mechanism.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Peng2010,

title = {Is slow-onset long-acting monoamine transport blockade to cocaine as methadone is to heroin? Implication for anti-addiction medications.},

author = {Xiao-Qing Peng and Zheng-Xiong Xi and Xia Li and Krista Spiller and Jie Li and Lauren Chun and Kuo-Ming Wu and Mark Froimowitz and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/20827272},

doi = {10.1038/npp.2010.133},

issn = {1740-634X (Electronic); 0893-133X (Linking)},

year  = {2010},

date = {2010-12-01},

journal = {Neuropsychopharmacology},

volume = {35},

number = {13},

pages = {2564--2578},

address = {Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, MD 21224, USA.},

abstract = {The success of methadone in treating opiate addiction has suggested that long-acting agonist therapies may be similarly useful for treating cocaine addiction. Here, we examined this hypothesis, using the slow-onset long-acting monoamine reuptake inhibitor 31,345, a trans-aminotetralin analog, in a variety of addiction-related animal models, and compared it with methadone's effects on heroin's actions in the same animal models. Systemic administration of 31,345 produced long-lasting enhancement of electrical brain-stimulation reward (BSR) and extracellular nucleus accumbens (NAc) dopamine (DA). Pretreatment with 31,345 augmented cocaine-enhanced BSR, prolonged cocaine-enhanced NAc DA, and produced a long-term (24-48 h) reduction in cocaine self-administration rate without obvious extinction pattern, suggesting an additive effect of 31,345 with cocaine. In contrast, methadone pretreatment not only dose-dependently inhibited heroin self-administration with an extinction pattern but also dose-dependently inhibited heroin-enhanced BSR and NAc DA, suggesting functional antagonism by methadone of heroin's actions. In addition, 31,345 appears to possess significant abuse liability, as it produces dose-dependent enhancement of BSR and NAc DA, maintains a low rate of self-administration behavior, and dose-dependently reinstates drug-seeking behavior. In contrast, methadone only partially maintains self-administration with an extinction pattern, and fails to induce reinstatement of drug-seeking behavior. These findings suggest that 31,345 is a cocaine-like slow-onset long-acting monoamine transporter inhibitor that may act as an agonist therapy for cocaine addiction. However, its pattern of action appears to be significantly different from that of methadone. Ideal agonist substitutes for cocaine should fully emulate methadone's actions, that is, functionally antagonizing cocaine's action while blocking monoamine transporters to augment synaptic DA.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Li2010,

title = {Activation of mGluR7s inhibits cocaine-induced reinstatement of drug-seeking behavior by a nucleus accumbens glutamate-mGluR2/3 mechanism in rats.},

author = {Xia Li and Jie Li and Eliot L Gardner and Zheng-Xiong Xi},

url = {https://www.ncbi.nlm.nih.gov/pubmed/20534005},

doi = {10.1111/j.1471-4159.2010.06851.x},

issn = {1471-4159 (Electronic); 0022-3042 (Linking)},

year  = {2010},

date = {2010-09-01},

journal = {J Neurochem},

volume = {114},

number = {5},

pages = {1368--1380},

address = {Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, DHHS, Baltimore, Maryland 21224, USA.},

abstract = {The metabotropic glutamate receptor 7 (mGluR7) has been reported to be involved in cocaine and alcohol self-administration. However, the role of mGluR7 in relapse to drug seeking is unknown. Using a rat relapse model, we found that systemic administration of AMN082, a selective mGluR7 allosteric agonist, dose-dependently inhibits cocaine-induced reinstatement of drug-seeking behavior. Intracranial microinjections of AMN082 into the nucleus accumbens (NAc) or ventral pallidum, but not the dorsal striatum, also inhibited cocaine-primed reinstatement, an effect that was blocked by local co-administration of MMPIP, a selective mGluR7 antagonist. In vivo microdialysis demonstrated that cocaine priming significantly increased extracellular dopamine in the NAc, ventral pallidum and dorsal striatum, while increasing extracellular glutamate in the NAc only. AMN082 alone failed to alter extracellular dopamine, but produced a slow-onset long-lasting increase in extracellular glutamate in the NAc only. Pre-treatment with AMN082 dose-dependently blocked both cocaine-enhanced NAc glutamate and cocaine-induced reinstatement, an effect that was blocked by MMPIP or LY341497 (a selective mGluR2/3 antagonist). These data suggest that mGluR7 activation inhibits cocaine-induced reinstatement of drug-seeking behavior by a glutamate-mGluR2/3 mechanism in the NAc. The present findings support the potential use of mGluR7 agonists for the treatment of cocaine addiction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Xi2008,

title = {Cannabinoid CB1 receptor antagonists attenuate cocaine's rewarding effects: experiments with self-administration and brain-stimulation reward in rats.},

author = {Zheng-Xiong Xi and Krista Spiller and Arlene C Pak and Jeremy Gilbert and Christopher Dillon and Xia Li and Xiao-Qing Peng and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/17728698},

doi = {10.1038/sj.npp.1301552},

issn = {0893-133X (Print); 0893-133X (Linking)},

year  = {2008},

date = {2008-06-01},

journal = {Neuropsychopharmacology},

volume = {33},

number = {7},

pages = {1735--1745},

address = {Neuropsychopharmacology Section, Chemical Biology Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, DHHS, Baltimore, MD 21224, USA. zxi@intra.nida.nih.gov},

abstract = {Previous studies suggest that cannabinoid CB1 receptors do not appear to be involved in cocaine's rewarding effects, as assessed by the use of SR141716A, a prototypic CB1 receptor antagonist and CB1-knockout mice. In the present study, we found that blockade of CB1 receptors by AM 251 (1-10 mg/kg), a novel CB1 receptor antagonist, dose-dependently lowered (by 30-70%) the break point for cocaine self-administration under a progressive-ratio (PR) reinforcement schedule in rats. The same doses of SR141716 (freebase form) maximally lowered the break point by 35%, which did not reach statistical significance. Neither AM 251 nor SR141716 altered cocaine self-administration under a fixed-ratio (FR2) reinforcement schedule. AM 251 (0.1-3 mg/kg) also significantly and dose-dependently inhibited (by 25-90%) cocaine-enhanced brain stimulation reward (BSR), while SR141716 attenuated cocaine's BSR-enhancing effect only at 3 mg/kg (by 40%). When the dose was increased to 10 or 20 mg/kg, both AM 251 and SR141716 became less effective, with AM 251 only partially inhibiting cocaine-enhanced BSR and PR cocaine self-administration, and SR141716 having no effect. AM 251 alone, at all doses tested, had no effect on BSR, while high doses of SR141716 alone significantly inhibited BSR. These data suggest that blockade of CB1 receptors by relatively low doses of AM 251 dose-dependently inhibits cocaine's rewarding effects, whereas SR141716 is largely ineffective, as assessed by both PR cocaine self-administration and BSR. Thus, AM 251 or other more potent CB1 receptor antagonists deserve further study as potentially effective anti-cocaine medications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Xi2006,

title = {Cannabinoid CB1 receptor antagonist AM251 inhibits cocaine-primed relapse in rats: role of glutamate in the nucleus accumbens.},

author = {Zheng-Xiong Xi and Jeremy G Gilbert and Xiao-Qing Peng and Arlene C Pak and Xia Li and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/16914679},

doi = {10.1523/JNEUROSCI.0726-06.2006},

issn = {1529-2401 (Electronic); 0270-6474 (Linking)},

year  = {2006},

date = {2006-08-16},

journal = {J Neurosci},

volume = {26},

number = {33},

pages = {8531--8536},

address = {Neuropsychopharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA. zxi@intra.nida.nih.gov},

abstract = {Blockade of cannabinoid CB1 receptors has been reported to inhibit cocaine- or cocaine cue-induced reinstatement of drug seeking. However, the mechanisms underlying this action are poorly understood. Given the importance of dopamine, glutamate, and GABA in cocaine reward and relapse, we studied the effects of AM251 [N-(piperidin-1-yl)-5-(4-iodophonyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole- 3-carboxamide], a novel highly selective CB1 receptor antagonist, on cocaine-primed reinstatement of drug-seeking behavior and on cocaine-induced changes in extracellular DA, glutamate, and GABA in the nucleus accumbens (NAc) under reinstatement conditions. We found that systemic administration of AM251 selectively inhibited cocaine-induced, but not sucrose plus sucrose cue-induced, reinstatement of reward-seeking behavior. AM251 alone did not trigger reinstatement. Local perfusion of AM251 into the NAc or the dorsal striatum also inhibited cocaine-triggered reinstatement. AM251 alone dose dependently elevated NAc glutamate in a voltage-dependent Na+ channel-dependent manner. AM251 did not affect NAc DA or GABA. Pretreatment with AM251 dose dependently inhibited cocaine-induced increases in NAc glutamate but not in DA. Blockade of NAc metabotropic glutamate mGluR2/3 receptors by LY341495 [(2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid] slightly facilitated cocaine-enhanced glutamate release but blocked the antagonism of cocaine-induced reinstatement by AM251. These data suggest the following: (1) CB1 receptors exert tonic inhibition over NAc glutamate release under cocaine-extinction conditions; (2) blockade of CB1 receptors by AM251 inhibits cocaine-enhanced NAc glutamate release and cocaine-triggered reinstatement; and (3) these effects appear to be mediated by activation of presynaptic mGluR2/3 autoreceptors secondary to AM251-induced increase (disinhibition) of NAc glutamate release.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hayes2003,

title = {Electrical and chemical stimulation of the basolateral complex of the amygdala reinstates cocaine-seeking behavior in the rat.},

author = {Robert J Hayes and Stanislav R Vorel and Jordan Spector and Xinhe Liu and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/12545331},

doi = {10.1007/s00213-002-1328-3},

issn = {0033-3158 (Print); 0033-3158 (Linking)},

year  = {2003},

date = {2003-07-07},

journal = {Psychopharmacology (Berl)},

volume = {168},

number = {1-2},

pages = {75--83},

address = {Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.},

abstract = {RATIONALE: The basolateral complex of the amygdala (BLC) is part of a neural circuit that is activated in humans during cocaine craving elicited by exposure to drug-related environmental cues. In animals, the BLC is necessary for cocaine-seeking behavior elicited by cocaine-associated cues. It has not been determined whether BLC activation is sufficient to reinstate cocaine seeking. OBJECTIVES: To determine whether electrical or excitatory amino-acid stimulation of the BLC is sufficient to induce reinstatement of cocaine seeking in rats. METHODS: Rats were catheterized and trained to lever-press for intravenous cocaine infusions on a fixed ratio (FR)-1 schedule of reinforcement. Once baseline cocaine-taking criteria were met, lever-pressing behavior was extinguished by substitution of saline for cocaine. After meeting criteria for extinction, animals were subjected to brief electrical (20 Hz, 400 microA or 2 Hz, 400 microA; 200 pulses per stimulation) or N-methyl- d-aspartate (NMDA; 250 ng/0.5 microl) BLC stimulation and lever pressing behavior was monitored. RESULTS. Electrical BLC stimulation with 20-Hz produced reinstatement of lever pressing previously associated with cocaine self-administration, while 2-Hz stimulation did not. Electrical stimulation of cerebellar and medial forebrain bundle loci did not reinstate cocaine seeking. Hence, the reinstatement was frequency dependent and anatomically selective. NMDA microinjections into the BLC also reinstated cocaine-seeking behavior. CONCLUSIONS: BLC stimulation is sufficient to reinstate cocaine-seeking behavior in the rat. These results are congruent with the hypothesis that the basolateral complex of the amygdala is part of a neural system mediating drug-seeking behavior.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vorel2002,

title = {Dopamine D3 receptor antagonism inhibits cocaine-seeking and cocaine-enhanced brain reward in rats.},

author = {Stanislav R Vorel and Charles Jr R Ashby and Mousumi Paul and Xinhe Liu and Robert Hayes and Jim J Hagan and Derek N Middlemiss and Geoffrey Stemp and Eliot L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/12417684},

issn = {1529-2401 (Electronic); 0270-6474 (Linking)},

year  = {2002},

date = {2002-11-01},

journal = {J Neurosci},

volume = {22},

number = {21},

pages = {9595--9603},

address = {Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland 21224, USA.},

abstract = {dopamine D3 receptor is preferentially localized to the mesocorticolimbic dopaminergic system and has been hypothesized to play a role in cocaine addiction. To study the involvement of the D3 receptor in brain mechanisms and behaviors commonly assumed to be involved in the addicting properties of cocaine, the potent and selective D3 receptor antagonist trans-N-[4-[2-(6-cyano-1,2,3,4-tetrahydroisoquinolin-2-yl)ethyl] cyclohexyl]-4-quinolininecarboxamide (SB-277011-A) was administered to laboratory rats, and the following measures were assessed: (1) cocaine-enhanced electrical brain-stimulation reward, (2) cocaine-induced conditioned place preference, and (3) cocaine-triggered reinstatement of cocaine seeking behavior. Systemic injections of SB-277011-A were found to (1) block enhancement of electrical brain stimulation reward by cocaine, (2) dose-dependently attenuate cocaine-induced conditioned place preference, and (3) dose-dependently attenuate cocaine-triggered reinstatement of cocaine seeking behavior. Thus, D3 receptor blockade attenuates both the rewarding effects of cocaine and cocaine-induced drug-seeking behavior. These data suggest an important role for D3 receptors in mediating the addictive properties of cocaine and suggest that blockade of dopamine D3 receptors may constitute a new and useful target for prospective pharmacotherapies for cocaine addiction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vorel2001,

title = {Relapse to cocaine-seeking after hippocampal theta burst stimulation.},

author = {S R Vorel and X Liu and R J Hayes and J A Spector and E L Gardner},

url = {https://www.ncbi.nlm.nih.gov/pubmed/11349151},

doi = {10.1126/science.1058043},

issn = {0036-8075 (Print); 0036-8075 (Linking)},

year  = {2001},

date = {2001-05-11},

journal = {Science},

volume = {292},

number = {5519},

pages = {1175--1178},

address = {Department of Neuroscience, Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA. robvorel@hotmail.com},

abstract = {Treatment efforts for cocaine addiction are hampered by high relapse rates. To map brain areas underlying relapse, we used electrical brain stimulation and intracranial injection of pharmacological compounds after extinction of cocaine self-administration behavior in rats. Electrical stimulation of the hippocampus containing glutamatergic fibers, but not the medial forebrain bundle containing dopaminergic fibers, elicited cocaine-seeking behavior dependent on glutamate in the ventral tegmental area. This suggests a role for glutamatergic neurotransmission in relapse to cocaine abuse. The medial forebrain bundle electrodes supported intense electrical self-stimulation. These findings suggest a dissociation of neural systems subserving positive reinforcement (self-stimulation) and incentive motivation (relapse).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}