Facilitation of hippocampal potentials by suramin

The influence of suramin, a suggested purino-receptor antagonist, on the evoked synaptic potentials recorded from hippocampal slices was evaluated. The suramin induced a nondecremental, concentration-dependent amplification of the slope of excitatory postsynaptic potential and magnitude of the population spike (long-term potentiation, LTP). The effect of suramin was completely abolished by adenylimidodiphosphate, a non-hydrolyzable analogue of ATP, and markedly reduced by NMDA-receptor antagonists DL-2-amino-5-phosphonovaleric acid and MK-801. These results indicate that, in addition to acting as an antagonist of P2 receptors, suramin is also able to facilitate hippocampal potentials in a way that involves mechanisms participating in induction of LTP.