Enhancement of hippocampal long-term potentiation induced by cocaine self-administration is maintained during the extinction of this behavior.
Drug addiction may involve learning and memory processes requiring the participation of hippocampal formation. One of the best studied examples of hippocampal synaptic plasticity is the long-term potentiation (LTP) which usually occurs when hippocampal synapses are stimulated with high-frequency stimulation. The aim of this work has been to study the effect of extinction of cocaine self-administration behavior on synaptic plasticity in rat hippocampal slices. LTP was induced using a tetanization paradigm consisting of a single train of high-frequency (100 Hz) stimulation for one second. This tetanization protocol evoked a greater and more perdurable LTP in slices obtained after 10 days of extinction of cocaine self-administration (1 mg/kg/injection) than that elicited in slices from saline self-administering (0.9% NaCl) animals. In addition, this LTP facilitation in animals which have followed the cocaine self-administration extinction protocol was very similar to that obtained in slices from cocaine self-administering animals. These results suggest that chronic cocaine self-administration induces enduring neuroadaptive changes in hippocampal synaptic plasticity which last even after the extinction of this behavior and that they may be involved in cocaine dependence.
del Olmo
Nuria
N
Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), C/Juan del Rosal no 10, 28040 Madrid, Spain.
Miguéns
Miguel
M
Higuera-Matas
Alejandro
A
Torres
Isabel
I
García-Lecumberri
Carmen
C
Solís
José María
JM
Ambrosio
Emilio
E
D000818:Animals; D001369:Axons / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003216:Conditioning, Operant / Q000187:drug effects; D004594:Electrophysiology; D005108:Extinction, Psychological / Q000187:drug effects*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D009474:Neurons / Q000187:drug effects; D051381:Rats; D011917:Rats, Inbred Lew; D012055:Reinforcement Schedule; D012646:Self Administration; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D003042:Cocaine