title: Effects of an adenosine A2A receptor blockade in the nucleus accumbens on locomotion, feeding, and prepulse inhibition in rats.
abstract: The nucleus accumbens (NAc) subserves behaviors governed by natural rewards, i.e., feeding or exploration, and has been implicated in control of prepulse inhibition (PPI), a measure of sensorimotor gating. The present study sought to determine whether a tonic stimulation of adenosine A(2A) receptors in the rat NAc is involved in control of spontaneous locomotor activity, feeding behavior, and PPI. To this end, bilateral microinfusions of a prodrug (MSX-3) (3 microg and 5 microg in 1 microl per side) of the selective A(2A) receptor antagonist MSX-2 or vehicle (1 microl per side) were administered into the NAc. Results show that blockade of intra-NAc adenosine A(2A) receptors by a high (5 microg), but not by a low (3 microg), dose of MSX-3 increased locomotor activity in an open field, reduced food intake, and delayed intake onset in food-deprived rats examined in a test cage with standard laboratory chow. Furthermore, PPI was significantly disrupted after intra-NAc infusion of 5 microg, but not 3 microg, MSX-3. These findings suggest that locomotor activity as well as intact PPI and feeding behavior rely on tonic activation of intra-NAc A(2A) receptors. The data add further support to the view that adenosine is a tonically active modulator of striatal function through actions on A(2A) receptors.
authors.affiliation: Department of Animal Physiology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Nagel
authors.forename: Henning
authors.initials: H
authors.lastname: Schladebach
authors.forename: Michael
authors.initials: M
authors.lastname: Koch
authors.forename: Isabel
authors.initials: I
authors.lastname: Schwienbacher
authors.forename: Christa E
authors.initials: CE
authors.lastname: Müller
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hauber
mesh_terms: D000818:Animals; D005247:Feeding Behavior / Q000187:drug effects* / Q000502:physiology; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000502:physiology; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D014970:Xanthines / Q000494:pharmacology
chemical_list: C113601:3-(3-hydroxypropyl)-8-(3-methoxystyryl)-7-methyl-1-propargylxanthine; C113602:MSX 3 compound; D058915:Purinergic P1 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1; D014970:Xanthines