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Intermittent cortical stimulation evokes sensitization to cocaine and enduring changes in matrix and striosome neuron responsiveness
Author(s) -
Canales Juan J.
Publication year - 2005
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.20149
Subject(s) - infralimbic cortex , stimulation , neuroscience , sensitization , striatum , psychology , cortex (anatomy) , stereotypy , prefrontal cortex , dopamine , amphetamine , cognition
Both the behavioral sensitization syndrome and the changes in the responsiveness of striatal neurons evoked by chronic cocaine exposure may be linked to enhanced neocortical activity, yet a direct demonstration of the effects of cortical stimulation on these parameters is lacking. We have found that repeated stimulation of the rat prelimbic cortex with picrotoxin (0.25 μg/0.25 μl, five injections on alternate days followed by 7‐day withdrawal) contributed to increase c‐Fos protein expression in the striosomes of the dorsolateral striatum, while producing the opposite effect in the matrix compartment, after a single exposure to cocaine (25 mg/kg). Moreover, rats exposed to cortical stimulation showed decreased locomotor activation but enhanced stereotypy following acute cocaine treatment. Thus, pulsatile stimulation of the prelimbic cortex facilitated modifications in striatal activity typically produced by chronic cocaine treatment and sensitized drug‐naïve animals to acute cocaine challenge. These results suggest that enhanced activation of the prelimbic cortex may contribute to the long‐term adaptations induced by cocaine on neural activity and behavior. Synapse 57:56–60, 2005. © 2005 Wiley‐Liss, Inc.