Adenosine A2A receptor knockout mice are partially protected against drug-induced catalepsy

Catalepsy assessed using the bar test was measured in both adenosine A(2A) receptor knockout (A(2A)R KO) and wild-type (A(2A)R WT) mice submitted to acute administration of the dopamine D-2 receptor antagonist haloperidol (0.5, 2, 4, 6 mg/kg i.p.), the dopamine D-1 antagonist SCH 23390 (0.3-3 mg/kg, s.c.), the vesicular monoamine transporter blocker reserpine (3-5 mg/kg, s.c.) or the acetylcholine muscarinic receptor agonist pilocarpine (25-50 mg/kg, i.p.). Except for reserpine, catalepsy scores were significantly lower in A(2A)R KO mice than in A(2A)R WT mice following low doses of these cataleptogenic agents. These results suggest that adenosine A(2A) receptors influence not only dopamine D-2 and D-1 receptor-mediated neurotransmission but also acetylcholine muscarinic receptor-mediated neurotransmission. NeuroReport 12:983-986 (C) 2001 Lippincott Williams & Wilkins.