title: Actions of adenosine A2A receptor antagonist KW-6002 on drug-induced catalepsy and hypokinesia caused by reserpine or MPTP.
abstract: BACKGROUND
  Current treatment of Parkinson's disease (PD) is based on dopamine replacement therapy, but this leads to long term complications, including dyskinesia. Adenosine A2A receptors are particularly abundant in the striatum and would be a target for an alternative approach to the treatment of PD.
  
  
  OBJECTIVE
  The purpose of this study is to examine the efficacy and potency of the novel selective adenosine A2A receptor antagonist (E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dhydro- 1H-purine-2,6- dione (KW-6002) in ameliorating the motor deficits in various mouse models of Parkinson's disease.
  
  
  METHODS
  We evaluated the efficacy and potency of KW-6002 and other reference compounds in the selective adenosine A2A receptor agonist 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosin e (CGS 21680)-, haloperidol- or reserpine-induced catalepsy models. The effect of KW-6002 on reserpine or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride(MPTP)-induced hypolocomotion was also examined.
  
  
  RESULTS
  The ED50s of KW-6002 in the reversal of CGS21680-induced and reserpine-induced catalepsy were 0.05 mg/kg, PO and 0.26 mg/kg, PO, respectively. Compared to the ED50 of other adenosine antagonists and dopamine agonist drugs, KW-6002 is over 10 times as potent in these models. KW-6002 also ameliorated the hypolocomotion (minimum effective dose; 0.16 mg/kg) induced by nigral dopaminergic dysfunction with MPTP or reserpine treatment. Combined administrations of subthreshold doses of KW-6002 and L-dopa (50 mg/kg, PO) exerted prominent effects on haloperidol-induced and reserpine-induced catalepsy, suggesting that there may be a synergism between the adenosine A2A receptor antagonist KW-6002 and dopaminergic agents.
  
  
  CONCLUSIONS
  To our knowledge, KW-6002 is the most potent and orally active adenosine A2A receptor antagonist in experimental models of Parkinson's disease, and may offer a new therapeutic approach to the treatment of Parkinson's disease.
authors.affiliation: Pharmaceutical Research Institute, Kyowa Hakko Kogyo Co. Ltd, Shizuoka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shiozaki
authors.forename: S
authors.initials: S
authors.lastname: Ichikawa
authors.forename: J
authors.initials: J
authors.lastname: Nakamura
authors.forename: S
authors.initials: S
authors.lastname: Kitamura
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwana
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000978:Antiparkinson Agents / Q000494:pharmacology; D014150:Antipsychotic Agents / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D002375:Catalepsy / Q000139:chemically induced / Q000517:prevention & control*; D015259:Dopamine Agents / Q000494:pharmacology*; D018476:Hypokinesia / Q000139:chemically induced / Q000517:prevention & control*; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D010627:Phenethylamines / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D011687:Purines / Q000494:pharmacology*; D012110:Reserpine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology
chemical_list: D000978:Antiparkinson Agents; D014150:Antipsychotic Agents; D015259:Dopamine Agents; D010627:Phenethylamines; D010726:Phosphodiesterase Inhibitors; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D011687:Purines; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C111599:istradefylline; D002110:Caffeine; D007980:Levodopa; D012110:Reserpine; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D013806:Theophylline; D000241:Adenosine