Effects of SCH 58261, an adenosine A(2A) receptor antagonist, on quinpirole-induced turning in 6-hydroxydopamine-lesioned rats: Lack of tolerance after chronic caffeine intake
P. Popoli et al., Effects of SCH 58261, an adenosine A(2A) receptor antagonist, on quinpirole-induced turning in 6-hydroxydopamine-lesioned rats: Lack of tolerance after chronic caffeine intake, NEUROPSYCH, 22(5), 2000, pp. 522-529
In unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats, a rodent model of
Parkinson's disease (PD), the adenosine A(2A) receptor antagonist SCH 5826
1 significantly increased (+180%, p<.01) the number of rotations induced by
a low dose of quinpirole (a dopamine D-2 receptor agonist), while it did n
ot significantly modify the effects of a comparably low dose of SKF 38393 (
a dopamine D-1 receptor agonist). The dose-dependent potentiating effects o
f SCH 58261 on quinpirole-induced turning were similar in caffeine-treated
rats (1 g/l in drinking water over 14 days) and control animals (tap water)
. The selective potentiating effects of SCH 58261 on D-2-dependent turning
confirm the existence of a potent and specific A(2A)/D-2 receptor-receptor
interaction. The persistence of the potentiating effects of SCH 58261 after
chronic caffeine intake suggests that no tolerance should develop towards
the antiparkinsonian effects of adenosine A(2A) receptor antagonists with c
hronic treatment. (C) American College of Neuropsychopharmacology.