Incubation of cocaine seeking following brief cocaine experience in mice is enhanced by mGluR1 blockade.
The incubation of cocaine craving describes the time-dependent augmentation of cue-induced cocaine seeking during withdrawal from prolonged cocaine self-administration and requires time-dependent changes in neuroplasticity at the level of glutamatergic synapses in the nucleus accumbens (NAc). In contrast to most studies that use multiple cocaine-cue conditioning sessions, the present study tested mice with limited cocaine experience (i.e., a single conditioning session) in the incubation of cue-mediated cocaine seeking and its associated changes in the glutamate system. Mice that self-administered cocaine during a single session exhibited a time-dependent increase in their response for the drug-associated cue as compared to mice that self-administered saline. This behavior was associated with changes in AMPA and NMDA receptor binding characteristics. Furthermore, Group I metabotropic glutamate receptor (mGluR1) mRNA levels were altered in several brain regions, including the NAc. Because of the pivotal role of mGluR1 in the control of cocaine-induced plasticity, we investigated the role of mGluR1 in the formation of drug cue-mediated cocaine seeking. After prolonged withdrawal, mice in which an mGluR1 antagonist was administered following cocaine self-administration displayed increased cocaine seeking compared to vehicle-treated mice. These results suggest that limited cocaine experience is sufficient to induce neurobiological changes that enable an initially neutral cue to acquire motivational value that increases over time, an effect that likely involves glutamate signaling through mGluR1.
Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 68159 Mannheim, Germany.
Briac
B
Halbout
Rick E
RE
Bernardi
Anita C
AC
Hansson
Rainer
R
Spanagel
D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003463:Cues; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D058999:Drug-Seeking Behavior / Q000187:drug effects / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists / Q000493:pharmacokinetics; D018691:Excitatory Amino Acid Antagonists / Q000493:pharmacokinetics; D005108:Extinction, Psychological / Q000187:drug effects; D005502:Food; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009714:Nucleus Accumbens / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012646:Self Administration; D013997:Time Factors; D014316:Tritium / Q000493:pharmacokinetics; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000493:pharmacokinetics
C516995:A-841720; D018765:Dopamine Uptake Inhibitors; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D006575:Heterocyclic Compounds, 3-Ring; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; D014316:Tritium; D016291:Dizocilpine Maleate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D003042:Cocaine
AMPA and NMDA receptors; addiction; cocaine self-administration; drug-seeking; metabotropic glutamate receptors; relapse