BLOCKADE BY 2,3-DIPROPYL-8-CYCLOPENTYLXANTHINE (CPX) OF PURINE PROTECTION AGAINST KAINATE NEUROTOXICITY

The adenosine A, receptor selective antagonist 1,3-dipropyl-8-cyclopen tylxanthine (CPX) has been administered systemically to rats together with the neurotoxin kainic acid. At the lower doses of CPX tested, 10 and 50 mu g/kg, which were sufficient to prevent the neuroprotective a ctivity of exogenous agonists, there was no exacerbation of the neuron al damage. At 250 mu g/kg, some enhancement of damage was found, which was also produced by 8-(p-sulphopenyl)theophylline, a non-selective x anthine which does not cross the blood-brain barrier. The results are consistent with the involvement of a central A, receptor in the neurop rotective activity of purines, and suggest that blockade of a peripher al adenosine receptor, possibly of the A, type, may increase neuronal damage.