Microinjection of the L-type calcium channel antagonist diltiazem into the ventral nucleus accumbens shell facilitates cocaine-induced conditioned place preferences.
BACKGROUND
Calcium (Ca2+) influx within the nucleus accumbens shell (NASh) can influence brain reward processes. We found previously that rats self-administer NMDA receptor antagonists (which block Ca2+ influx through NMDA receptors) into the NASh. We also found that manipulations which increase expression of Ca2+-permeable AMPA receptors within this region make cocaine aversive. Here we examined if Ca2+ influx via L-type Ca2+ channels within the NASh would influence cocaine reward.


METHODS
Rats received bilateral microinjections of the L-type Ca2+ channel antagonist diltiazem into the ventral NASh prior to place conditioning with systemic cocaine.


RESULTS
Microinjections of diltiazem (10 nmol/hemisphere) into the ventral NASh facilitated the ability of a sub-threshold dose of cocaine (5.0 mg/kg) to establish place preferences, but did not affect place conditioning on their own (5.0-40 nmol/hemisphere). Microinjections into more dorsal regions had no effects.


CONCLUSIONS
Blockade of Ca2+ influx through L-type channels Ca2+ within the ventral NASh increases cocaine reward.
Chartoff
Elena H
EH
Behavioral Genetics Laboratory, Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478, USA.
Pliakas
Andrea M
AM
Carlezon
William A
WA
D000779:Anesthetics, Local / Q000008:administration & dosage; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D002755:Choice Behavior / Q000187:drug effects*; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects*; D004110:Diltiazem / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D008845:Microinjections; D009714:Nucleus Accumbens / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000779:Anesthetics, Local; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D004110:Diltiazem; D003042:Cocaine