An emerging clinical approach to treat substance abuse disorders involves a form of cognitive-behavioral therapy whereby addicts learn to reduce their reactivity to drug-paired stimuli through cue-exposure or extinction training. It is, however, unlikely that extinction training would be consistently effective as a stand- alone treatment in populations that have abused drugs long-term because the key memory systems that are recruited during extinction training are impaired by long-term drug use. There is a critical need to understand mechanisms underlying extinction learning and to establish viable strategies to increase the efficacy of extinction therapies for substance abuse disorders. Key elements of the proposed research plan build on recent advances made in the treatment of conditioned fear and anxiety and other cognitive disorders by pharmacological modulation of glycine, an obligatory co-transmitter at the NMDA glutamate receptor complex.
The specific aims of the proposed research in rats and non-human primates are to: 1) elucidate the neurobiological substrates of extinction learning; 2) evaluate selected glycine site partial agonists and glycine transporter-1 (GlyT1) inhibitors as candidate pharmacotherapies to increase the efficacy of extinction training; and 3) determine neurobiological substrates of glycine site modulation of extinction learning. The intravenous cocaine self-administration procedure will be used in the proposed studies because the contingency between drug delivery and behavior is likely paramount for understanding the persistent abuse of drugs in people. Measurement of Fos protein expression (a marker for neuronal activation) and evaluation with anisomycin (an inhibitor of de novo protein synthesis) will be used in rats to investigate the neurobiological substrates of extinction learning following cocaine self-administration training. In addition, the proposed research in rats and non-human primates will specifically investigate the effects of the partial glycine agonist D-cycloserine and selective GlyT1 inhibitors for their ability to accelerate extinction learning and to subsequently reduce cocaine cue reactivity and re-acquisition of cocaine self-administration. Animal research involving pharmacological modulation of learning and memory is well-served by an integrated comparative strategy using appropriately selected laboratory animals. This approach is especially relevant for research involving cognitive enhancing drugs, where non-human primates can serve as a key translational interface for the development of pharmacotherapies. ? ? ?

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
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Special Emphasis Panel (ZDA1-RXL-E (23))
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Volman, Susan
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Boston University
Schools of Arts and Sciences
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Gauthier, Jamie M; Lin, Amy; Nic Dhonnchadha, Bríd Á et al. (2017) Environmental enrichment facilitates cocaine-cue extinction, deters reacquisition of cocaine self-administration and alters AMPAR GluA1 expression and phosphorylation. Addict Biol 22:152-162
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Szalay, Jonathan J; Jordan, Chloe J; Kantak, Kathleen M (2013) Neural regulation of the time course for cocaine-cue extinction consolidation in rats. Eur J Neurosci 37:269-77
Nic Dhonnchadha, Brid A; Pinard, Emmanuel; Alberati, Daniela et al. (2012) Inhibiting glycine transporter-1 facilitates cocaine-cue extinction and attenuates reacquisition of cocaine-seeking behavior. Drug Alcohol Depend 122:119-26
Hofmann, Stefan G; Huweler, Ruth; MacKillop, James et al. (2012) Effects of D-cycloserine on craving to alcohol cues in problem drinkers: preliminary findings. Am J Drug Alcohol Abuse 38:101-7
Nic Dhonnchadha, B A; Lovascio, B F; Shrestha, N et al. (2012) Changes in expression of c-Fos protein following cocaine-cue extinction learning. Behav Brain Res 234:100-6
Achat-Mendes, Cindy; Nic Dhonnchadha, Bríd Á; Platt, Donna M et al. (2012) Glycine transporter-1 inhibition preceding extinction training inhibits reacquisition of cocaine seeking. Neuropsychopharmacology 37:2837-45
Kantak, K M; Nic Dhonnchadha, B A (2011) Pharmacological enhancement of drug cue extinction learning: translational challenges. Ann N Y Acad Sci 1216:122-37
Nic Dhonnchadha, Brid Aine; Kantak, Kathleen M (2011) Cognitive enhancers for facilitating drug cue extinction: insights from animal models. Pharmacol Biochem Behav 99:229-44
Szalay, Jonathan J; Morin, Nicole D; Kantak, Kathleen M (2011) Involvement of the dorsal subiculum and rostral basolateral amygdala in cocaine cue extinction learning in rats. Eur J Neurosci 33:1299-307

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