CN-induced depression of CA1 excitatory synaptic transmission is blocked by an adenosine receptor antagonist.A, CA1 population spikes were elicited by stimulating stratum radiatum at 0.1 Hz. The initial positive slope reflects the rising phase of the EPSP, and the sharp downward (negative) deflection is the population spike (50% maximal). Bath application of 100 μm KCN for 5 min reversibly depressed transmission.B, Dot plots of CA1 population spike amplitude in another slice. Top, Time course of CN-induced depression. Middle, The action of CN was strongly attenuated by 8-SPT. Bottom, Partial recovery of the action of CN after washing slice for 60 min. CN superfusion is marked by arrows. C, D, Dose–response curves for depression of EPSP (C) and population spike (D); 8-SPT shifted both dose–response curves to the right. One hundred percent represents full suppression of fEPSP and population spikes. IC50 for CN action is indicated bydashed lines. Data from several experiments were pooled to obtain mean ± SEM (n = 5–9).
