2000 Volume 31 Issue 2 Pages 199-210
Caffeine is known to act as an adensine receptor antagonist (in vitro study), however the exact mechanisms of its actions in the CNS remain unclear. Therefore the present study has been designed to examine the effects of caffeine on behavioral action, and whether its effecs mediate adenosine A_2 receptor using behavioral and pharmacological method. As measurement of behavioral activity, locomotor activity (total distance and time) and frequency of standing on hind limbs (rearing) were evaluated with the open-field apparatus. The results was as follow : Administration of caffeine and selective adenosine A_2 receptor antagonist (DMPX) dose-dependently increased in locomotor activity in rats. Behavioral stimulant effects of caffeine (10mg and 30mg/kg, I.P.) and 3,7-dimethyl-1-propargylxanthine (DMPX ; 1.3mg/kg, I.P.) were dose-dependently attenuated by selective adenosine A_2 receptor agonist, 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA, I.P.), respectively. It was suggested that caffeine-induced stimulating effects on behavioral action in the CNS were direct consequences of adenoceptor blockade.
