Transient and selective blockade of adenosine A1-receptors by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) causes sustained epileptiform activity in hippocampal CA3 neurons of guinea pigs

The effects of endogenously released adenosine on the excitability
of hippocampal neurons were studied using the novel and highly
selective adenosine A1-receptor antagonist
8-cyclopentyl-1,3-dipropylxanthine (DPCPX). Extra- and
intracellular recordings performed in area CA1 and CA3 of the
guinea pig hippocampal slice preparation revealed that a transient
suppression of an inhibitory purinergic tonus by DPCPX leads to
sustained interictal-like epileptiform activity arising in area
CA3. Once induced, the spontaneous burst discharges were apparently
irreversible within the observation period, even after prolonged
washout (2–3h) in normal solution. In contrast, the hyperpolarizing
action of exogenous adenosine, which was substantially reduced by
DPCPX, recovered within 30–60 min of drug washout, indicating that
DPCPX was not irreversibly bound to the A1-receptor.