Extinction training regulates neuroadaptive responses to withdrawal from chronic cocaine self-administration.
Cocaine produces multiple neuroadaptations with chronic repeated use. Many of these neuroadaptations can be reversed or normalized by extinction training during withdrawal from chronic cocaine self-administration in rats. This article reviews our past and present studies on extinction-induced modulation of the neuroadaptive response to chronic cocaine in the mesolimbic dopamine system, and the role of this modulation in addictive behavior in rats. Extinction training normalizes tyrosine hydroxylase levels in the nucleus accumbens (NAc) shell, an effect that could help ameliorate dysphoria and depression associated with withdrawal from chronic cocaine use. Extinction training also increases levels of GluR1 and GluR2/3 AMPA receptor subunits, while normalizing deficits in NR1 NMDA receptor subunits, in a manner consistent with long-term potentiation of excitatory synapses in the NAc shell. Our results suggest that extinction-induced increases in AMPA and NMDA receptors may restore deficits in cortico-accumbal neurotransmission in the NAc shell and facilitate inhibitory control over cocaine-seeking behavior. Other changes identified by gene expression profiling, including up-regulation in the AMPA receptor aggregating protein Narp, suggest that extinction training induces extensive synaptic reorganization. These studies highlight potential benefits for extinction training procedures in the treatment of drug addiction.
Department of Psychiatry, The Seay Center for Basic and Applied Research in Psychiatric Illness, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070 USA. david.self@utsouthwestern.edu
David W
DW
Self
Kwang-Ho
KH
Choi
Diana
D
Simmons
John R
JR
Walker
Cynthia S
CS
Smagula
D000222:Adaptation, Physiological; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology; D003042:Cocaine / Q000008:administration & dosage*; D004195:Disease Models, Animal; D005108:Extinction, Psychological / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000502:physiology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012646:Self Administration; D013375:Substance Withdrawal Syndrome / Q000378:metabolism* / Q000503:physiopathology; D019966:Substance-Related Disorders / Q000503:physiopathology
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D003042:Cocaine