title: Divergent effects of D₂/₃ receptor activation in the nucleus accumbens core and shell on impulsivity and locomotor activity in high and low impulsive rats.
abstract: BACKGROUND
  Previously we demonstrated reduced D2/3 receptor availability in the ventral striatum of hyper-impulsive rats on the five-choice serial reaction time task (5-CSRTT). However, the anatomical locus of D2/3 receptor dysfunction in high impulsive (HI) rats is unknown.
  
  
  OBJECTIVE
  In the present study, we investigated whether D2/3 receptor dysfunction in HI rats is localised to the core or shell sub-regions of the nucleus accumbens (NAcb).
  
  
  METHODS
  Rats were selected for low (low impulsive, LI) and high impulsivity on the 5-CSRTT and implanted with guide cannulae targeting the NAcb core and shell. The D2/3 receptor agonist quinpirole was locally injected in the NAcb (0.1, 0.3 and 1 μg per infusion) and its effects investigated on the performance of LI and HI rats on the 5-CSRTT as well as spontaneous locomotor activity in an open field.
  
  
  RESULTS
  Intra-NAcb core quinpirole increased premature responding in HI rats but not in LI rats. In contrast, intra-NAcb shell quinpirole strongly increased locomotor activity in HI rats, unlike LI rats. This effect was blocked by intra-NAcb shell infusions of the D2/3 receptor antagonist nafadotride (0.03 μg). However, nafadotride was ineffective in blocking the effects of intra-NAcb core quinpirole on premature responding in HI rats.
  
  
  CONCLUSIONS
  These findings indicate that impulsivity and hyperactivity are separately regulated by core and shell sub-regions of the NAcb and that HI rats show an enhanced response to D2/3 receptor activation in these regions. These results suggest that the symptom clusters of hyperactivity and impulsivity in attention-deficit hyperactivity disorder may be neurally dissociable at the level of the NAcb.
authors: Department of Psychology, University of Almeria, Almeria, Spain.
authors: M
authors: M
authors: Moreno
authors: D
authors: D
authors: Economidou
authors: A C
authors: AC
authors: Mar
authors: C
authors: C
authors: López-Granero
authors: D
authors: D
authors: Caprioli
authors: D E
authors: DE
authors: Theobald
authors: A
authors: A
authors: Fernando
authors: A H
authors: AH
authors: Newman
authors: T W
authors: TW
authors: Robbins
authors: Jeffrey W
authors: JW
authors: Dalley
mesh_terms: D000818:Animals; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006948:Hyperkinesis / Q000378:metabolism; D007175:Impulsive Behavior / Q000378:metabolism*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009281:Naphthalenes / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology; D019257:Quinpirole / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D009281:Naphthalenes; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D019257:Quinpirole; C097285:nafadotride