Dose-response analysis of locomotor activity and stereotypy in dopamine D3 receptor mutant mice following acute amphetamine

• Published in: Synapse (New York, N.Y.) Vol. 60; no. 5; pp. 399 - 405
• Main Authors: McNamara, Robert K., Logue, Aaron, Stanford, Kevin, Xu, Ming, Zhang, Jianhua, Richtand, Neil M.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.10.2006
• Subjects: amphetamine; Amphetamine - pharmacology; Animals; Brain - drug effects; Brain - metabolism; Brain - physiopathology; Brain Chemistry - drug effects; Brain Chemistry - genetics; Disease Models, Animal; Dopamine - metabolism; Dopamine Agents - pharmacology; dopamine D3 receptor; dose-response; Dose-Response Relationship, Drug; locomotor activity; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Motor Activity - drug effects; Motor Activity - genetics; mutant mice; Neural Inhibition - drug effects; Neural Inhibition - genetics; Receptors, Dopamine D3 - agonists; Receptors, Dopamine D3 - genetics; Stereotypic Movement Disorder - genetics; Stereotypic Movement Disorder - metabolism; Stereotypic Movement Disorder - physiopathology; stereotypy; Synaptic Transmission - drug effects; Synaptic Transmission - genetics
• ISSN: 0887-4476; 1098-2396
• DOI: 10.1002/syn.20315

Accumulating evidence suggests that dopamine D3 receptor (D3R) stimulation is inhibitory to spontaneous and psychostimulant‐induced locomotion through opposition of concurrent D1R and D2R‐mediated signaling. To evaluate this model, we used homozygous D3R mutant mice and wild‐type controls to investigate the role of the D3R in locomotor activity and stereotypy stimulated by acute amphetamine (AMPH) (0.2, 2.5, 5.0, 10.0 mg/kg). At the lowest dose tested (0.2 mg/kg), neither D3R mutant mice nor wild‐type mice exhibited measurable change in locomotor activity or stereotypy relative to their respective saline‐treated controls. D3R mutant mice exhibited a significantly greater increase in locomotor activity, but not stereotypy, relative to wild‐type mice in response to treatment with AMPH 2.5 mg/kg. AMPH‐induced locomotor activity and stereotypy were similar in both wild‐type and D3R mutant mice at both the 5.0 and 10 mg/kg AMPH doses. These findings provide further support for an inhibitory role for the D3R in AMPH‐induced locomotor activity, and demonstrate a more limited role for the D3R in modulating AMPH‐induced stereotypy. Synapse 60:399–405, 2006. © 2006 Wiley‐Liss, Inc.