title: Differential effects of dopaminergic agents on locomotor sensitisation and on the reinstatement of cocaine-seeking and food-seeking behaviour.
abstract: BACKGROUND
  The dopaminergic pathways are involved in natural and drug reward related processes.
  
  
  OBJECTIVE
  To compare the respective involvement of the dopaminergic receptors D1, D2 and D3 in natural-seeking versus drug-seeking behaviour and evaluate any concomitant expression of locomotor sensitisation.
  
  
  METHODS
  In separate experiments, male Wistar rats were trained to self-administer cocaine (0.25 mg/infusion) or to press a lever to obtain food pellets. Following a prolonged period of extinction, reinstatement of lever responding was measured following non-contingent food delivery, cocaine (15 mg/kg), D1-like (SKF 82958, 0.25 mg/kg), D2-like (quinelorane, 0.25 mg/kg) and D3-like (7-OHDPAT, 0.25 mg/kg) agonists. To demonstrate parallel expression of behavioural sensitisation, locomotor activity was recorded during the reinstatement sessions.
  
  
  RESULTS
  Cocaine and quinelorane administrations reinstated cocaine-seeking behaviour and induced the expression of locomotor sensitisation, whereas SKF 82958 and 7-OHDPAT had either no effect or non-specific effects. In the food-seeking experiment, we found that quinelorane and 7-OHDPAT did not reinstate lever pressing. Cocaine increased responding on both active and inactive levers, whereas SKF 82958 had a more specific effect with higher responding on the previously food-associated lever.
  
  
  CONCLUSIONS
  Our results indicate that expression of locomotor sensitisation and reinstatement of cocaine-seeking but not food-seeking behaviours are in part supported by common dopaminergic substrates, among which the D2 receptors play a crucial role.
authors.affiliation: Laboratoire de Neuropsychobiologie des Désadaptations, UMR CRNS 5541, Université Victor Ségalen, Bordeaux 2, 146, rue Leo Saignat, BP 31, 33076 Bordeaux Cedex, France. d_carine@yahoo.fr
authors.forename: C
authors.initials: C
authors.lastname: Dias
authors.forename: S
authors.initials: S
authors.lastname: Lachize
authors.forename: V
authors.initials: V
authors.lastname: Boilet
authors.forename: E
authors.initials: E
authors.lastname: Huitelec
authors.forename: M
authors.initials: M
authors.lastname: Cador
mesh_terms: D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003463:Cues; D018491:Dopamine Agonists / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D005108:Extinction, Psychological / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010775:Photic Stimulation; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000819:agonists; D017448:Receptors, Dopamine D2 / Q000819:agonists; D050637:Receptors, Dopamine D3; D012008:Recurrence; D012201:Reward; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
chemical_list: D001552:Benzazepines; D018491:Dopamine Agonists; D018765:Dopamine Uptake Inhibitors; C493595:Drd3 protein, rat; D011804:Quinolines; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; C071262:SK&F 82958; D003042:Cocaine; C031349:7-hydroxy-2-N,N-dipropylaminotetralin; C047726:quinelorane