Effect of intra-accumbens dopamine receptor agents on reactivity to spatial and non-spatial changes in mice.
BACKGROUND
Some evidence suggests an involvement of nucleus accumbens in spatial learning. However, it is controversial whether the mesoaccumbens dopaminergic pathways play a specific role in the acquisition of spatial information.


OBJECTIVE
The goal of these experiments was to investigate the effect of dopaminergic manipulations in the nucleus accumbens on a non-associative task designed to estimate the ability to encode/transmit spatial and non-spatial information.


METHODS
The effects of focal administrations of the D1 and D2 dopamine receptor antagonists, SCH 23390 (6.25, 12.5, 50 ng/side) and sulpiride (12.5, 50, 100 ng/side), respectively, and dopamine (DA; 1.25 and 2.5 microg/side) into the nucleus accumbens were studied on reactivity to spatial and non-spatial changes in an open field with objects.


RESULTS
Both SCH 23390 and sulpiride impaired reactivity to spatial change. However, several differences were found in the effects induced by the two DA antagonists. SCH 23390 did not affect locomotor activity and only slightly impaired exploration of the novel object. On the contrary, the D2 antagonist, induced a general, dose-dependent, impairment on all variables measured. Local administration of DA increased locomotor activity, but did not affect reactivity to spatial and non-spatial changes.


CONCLUSIONS
These results demonstrate a facilitatory role of mesoaccumbens dopamine in the acquisition of spatial information. Moreover, they suggest that nucleus accumbens D1 DA receptors, play a more selective role in the modulation of spatial learning than accumbens D2 DA receptors.
Coccurello
R
R
Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, Rome, Italy.
Adriani
W
W
Oliverio
A
A
Mele
A
A
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D005106:Exploratory Behavior / Q000187:drug effects; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D007858:Learning / Q000187:drug effects*; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D011954:Receptors, Dopamine / Q000502:physiology*; D013037:Spatial Behavior / Q000187:drug effects*; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D011954:Receptors, Dopamine; D013469:Sulpiride; D004298:Dopamine