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Psychopharmacology (Berl). 2019 Jan;236(1):531-543. doi: 10.1007/s00213-018-5071-9. Epub 2018 Nov 8.

Phosphoproteomic analysis of cocaine memory extinction and reconsolidation in the nucleus accumbens.

Author information

1
Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, 450 Technology Dr., Suite 223, Pittsburgh, PA, 15219, USA. torregrossam@upmc.edu.
2
Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, 450 Technology Dr., Suite 223, Pittsburgh, PA, 15219, USA.
3
Department of Molecular Biophysics and Biochemistry, Yale/Keck MS & Proteomics Resource, Yale University, New Haven, CT, USA.
4
Department of Psychiatry, Yale University, New Haven, CT, USA.
5
Department of Pharmacology, Yale University, New Haven, CT, USA.
6
Department of Psychology, Yale University, New Haven, CT, USA.

Abstract

RATIONALE:

Environmental stimuli, or cues, associated with the use of drugs such as cocaine are one of the primary drivers of relapse. Thus, identifying mechanisms to reduce the motivational properties of drug cues is an important research goal.

OBJECTIVES:

The purpose of this study was to identify cellular signaling events in the nucleus accumbens (NAc) that are induced when a cocaine cue memory is either extinguished through repeated cue presentation in the absence of drug, or when the memory is reactivated and reconsolidated by a brief cue re-exposure. Signaling events specific to extinction or reconsolidation represent potential targets for pharmacotherapeutics that may enhance extinction or disrupt reconsolidation to reduce the likelihood of relapse.

METHODS:

Male Sprague-Dawley rats were trained to self-administer cocaine paired with an audiovisual cue. Following a period of self-administration, the memory for the cocaine-associated cue was either extinguished, reactivated, or not manipulated (control) 15 min before sacrifice. Tissue from the NAc was subsequently analyzed using mass spectrometry based phosphoproteomics to identify cellular signaling events induced by each condition.

RESULTS:

Extinction and reconsolidation of the cocaine cue memory produced both common and distinct changes in protein phosphorylation. Notably, there were no significant changes in protein phosphorylation that were modulated in the opposite direction by the two behavioral conditions. Comparison of NAc phosphoproteomic changes to previously identified changes in the basolateral amygdala (BLA) revealed that cue extinction increases phosphorylation at serine (S) 883 of the GABAB receptor subunit 2 and on S14 of syntaxin 1a in both regions, while no common regional signaling events were identified in the reconsolidation group.

CONCLUSIONS:

Phosphoproteomics is a useful tool for identifying signaling cascades involved in different memory processes and revealed novel potential targets for selectively targeting extinction versus reconsolidation of a cocaine cue memory. Furthermore, cross region analysis suggests that cue extinction may produce unique signaling events associated with increased inhibitory signaling.

KEYWORDS:

Cocaine; Extinction; Memory; Phosphorylation; Proteomics; Reconsolidation; Self-administration

PMID:
30411139
PMCID:
PMC6374162
[Available on 2020-01-01]
DOI:
10.1007/s00213-018-5071-9
[Indexed for MEDLINE]

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