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An investigation of interactions between hypocretin/orexin signaling and glutamate receptor surface expression in the rat nucleus accumbens under basal conditions and after cocaine exposure.
Neuroscience Letters (2013)
  • Ainhoa Plaza-Zabala, Pompeu Fabra University
  • Xuan Li, Rosalind Franklin University of Medicine and Science
  • Mike Milovanovic, Rosalind Franklin University of Medicine and Science
  • Jessica A. Loweth, Rowan University School of Osteopathic Medicine
  • Rafael Maldonado, Pompeu Fabra University
  • Fernando Berrendero, Pompeu Fabra University
  • Marina E. Wolf, Rosalind Franklin University of Medicine and Science
Abstract
Hypocretin peptides are critical for the effects of cocaine on excitatory synaptic strength in the ventral tegmental area (VTA). However, little is known about their role in cocaine-induced synaptic plasticity in the nucleus accumbens (NAc). First, we tested whether hypocretin-1 by itself could acutely modulate glutamate receptor surface expression in the NAc, given that hypocretin-1 in the VTA reproduces cocaine's effects on glutamate transmission. We found no effect of hypocretin-1 infusion on AMPA or NMDA receptor surface expression in the NAc, measured by biotinylation, either 30 min or 3h after the infusion. Second, we were interested in whether changes in hypocretin receptor-2 (Hcrtr-2) expression contribute to cocaine-induced plasticity in the NAc. As a first step towards addressing this question, Hcrtr-2 surface expression was compared in the NAc after withdrawal from extended-access self-administration of saline (control) versus cocaine. We found that surface Hcrtr-2 levels remain unchanged following 14, 25 or 48 days of withdrawal from cocaine, a time period in which high conductance GluA2-lacking AMPA receptors progressively emerge in the NAc. Overall, our results fail to support a role for hypocretins in acute modulation of glutamate receptor levels in the NAc or a role for altered Hcrtr-2 expression in withdrawal-dependent synaptic adaptations in the NAc following cocaine self-administration.
Keywords
  • hypocretin,
  • orexin,
  • cocaine,
  • glutamate receptor,
  • synaptic plasticity,
  • nucleus accumbens
Publication Date
January 12, 2013
DOI
10.1016/j.neulet.2013.10.038
Citation Information
Ainhoa Plaza-Zabala, Xuan Li, Mike Milovanovic, Jessica A. Loweth, et al.. "An investigation of interactions between hypocretin/orexin signaling and glutamate receptor surface expression in the rat nucleus accumbens under basal conditions and after cocaine exposure." Neuroscience Letters Vol. 557 Iss. Part B (2013) p. 101 - 106 ISSN: 0304-3940
Available at: http://works.bepress.com/jessica-loweth/12/