title: Repeated stimulation of L-type calcium channels in the rat ventral tegmental area mimics the initiation of behavioral sensitization to cocaine.
abstract: BACKGROUND
  A substantial body of evidence indicates that ion flux through L-type calcium channels and N-methyl-D-aspartate (NMDA) receptors contributes to behavioral sensitization to cocaine.
  
  
  OBJECTIVE
  The following experiments were designed to evaluate the role of calcium influx through L-type calcium channels or NMDA receptors in the ventral tegmental area (VTA) in the initiation of behavioral sensitization to cocaine.
  
  
  METHODS
  The L-type calcium channel agonist BayK 8644, the glutamate agonist NMDA, or vehicle was microinjected into the VTA on 3 consecutive days. Following a 2-week withdrawal period, all rats received a challenge injection of cocaine (15 mg/kg, i.p.) in order to assess potential cross-sensitization with the NMDA or BayK 8644 pretreatments.
  
  
  RESULTS
  Repeated intra-VTA microinjections of BayK 8644, but not NMDA, resulted in an augmentation of the behavioral response to cocaine.
  
  
  CONCLUSIONS
  These results indicate that calcium influx through L-type calcium channels produces neurophysiological adaptations that mimic those resulting from intermittent exposure to cocaine.
authors.affiliation: Department of Pharmacology, Boston University School of Medicine, MA 02118, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Licata
authors.forename: A Y
authors.initials: AY
authors.lastname: Freeman
authors.forename: A F
authors.initials: AF
authors.lastname: Pierce-Bancroft
authors.forename: R C
authors.initials: RC
authors.lastname: Pierce
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D008297:Male; D008845:Microinjections; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists; D013239:Stereotyped Behavior / Q000187:drug effects; D017557:Ventral Tegmental Area / Q000502:physiology*
chemical_list: D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D018765:Dopamine Uptake Inhibitors; D016194:Receptors, N-Methyl-D-Aspartate; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D003042:Cocaine