FACILITATION OF HIPPOCAMPAL POTENTIALS BY SURAMIN

The influence of suramin, a suggested purinoreceptor antagonist, on th e evoked synaptic potentials recorded from hippocampal slices was eval uated. The suramin induced a nondecremental, concentration-dependent a mplification of the slope of excitatory postsynaptic potential and mag nitude of the population spike (long-term potentiation, LTP). The effe ct of suramin was completely abolished by adenylimidodiphosphate, a no nhydrolyzable analogue of ATP, and markedly reduced by NMDA-receptor a ntagonists DL-2-amino-5-phosphonovaleric acid and MK-801. These result s indicate that, in addition to acting as an antagonist of P-2 recepto rs, suramin is also able to facilitate hippocampal potentials in a way that involves mechanisms participating in induction of LTP.