Fig. 3.

Subthreshold effects of group I mGluR activation on individual motoneurons. A: schematic showing the experimental setup with a patch pipette targeting a spinal motoneuron and glass suction electrodes attached to the second lumbar (L2) ventral roots. B: antidromic action potentials recorded from a motoneuron in response to stimulation of the ipsilateral ventral root. Arrow indicates stimulus artefact. C and D: resting membrane potential of motoneurons was depolarized in response to DHPG (50 μM) application (n = 11). E: current recorded in response to brief sub-threshold voltage steps (10 ms, −70 to −55 mV) in a motoneuron held at −60 mV in control conditions, in the presence of DHPG, and following drug washout. F: membrane resistance was significantly decreased by DHPG application. G: DHPG-induced currents appeared to have a linear current-voltage relationship, with an extrapolated reversal potential of approximately −30 mV (n = 11). *Significantly different from control.