Figure 4.

Glutamatergic nature of PPRF synapses on PH neurons and the depolarizing effect of cholinergic inputs on the same postsynaptic neuron. A, Top, EPSP evoked in a PH neuron by a single subthreshold stimulus applied to the PPRF. Note that the synaptic potential was not affected by atropine (1.5 μm) but that superfusion with CNQX (10 μm) completely removed the evoked EPSP. B, Train (200 Hz) stimulation of the same PPRF site evoked a large and sustained post-train depolarization of the same PH neuron. This sustained depolarization was impossible to evoke in the presence of atropine sulfate (1.5 μm).