Fig. 10.

Endogenous activation of mGluRs by high-frequency activity in excitatory synapses onto trigeminal motoneurons.A, Compound excitatory synaptic currents in a motoneuron held at −60 mV. Stimulus intensity is indicated by each sample trace (left). Time and current calibrations apply to all traces in A. Stimulus artifacts were partially deleted.B, Schematic diagram of a typical experiment. Pharmacological conditions are indicated by the barsoverlying the protocol. Time breaks are shown. Ramp icons represent the acquisition of a steady-state I–V curve via slow voltage ramp commands (8 mV/sec). The inverted comb icon represents 30 Hz stimulation (40 μA intensity) of premotoneurons for 1 min (as labeled). C, Subtracted currents from the protocols illustrated in B. Abscissa and ordinate axes are identical for all three plots.