Adenosine mediates outward current and increase in input conductance elicited by CN. Intracellular recording (with 3m KCl electrode) was from a CA1 neuron under voltage clamp in the presence of 0.5 μm TTX. Transmitter-mediated responses were minimized further by 2 mm kynurenate and 10 μm bicuculline. Hyperpolarizing pulses (−20 mV, 500 msec—monitored on topmost trace) and corresponding currents are shown on expanded time scale before, during, and after CN application. Zero current levels are indicated by horizontal arrows, at left of traces. Note substantial outward current, as well as increased conductance (A), which was blocked by 8-SPT (B). C was recorded after 45 min wash.