High Frequency Stimulation of the Subthalamic Nucleus Leads to Presynaptic GABA(B)-Dependent Depression of Subthalamo-Nigral Afferents
Figure 5
Compound glutamate- and GABA-induced ion currents during and after multi-unit HFS-STN.
Responses of SNr neurons to Macrostim in the STN. Note that the driving force for the transmitter-induced currents is 60 mV for glutamate but only 50 mV for GABA. A) Recordings in the presence of gabazine (15 µM) to show compound glutamatergic ion currents. The calibration bars in (B) also apply to (A). Note strong attenuation with train repetition. B) Recordings in the presence of DNQX (10 µM) and APV (50 µM). Note that a fraction of the GABA-induced chloride current remains during and after HFS-STN. C,D) Enlarged individual traces from same experiments as in A,B, respectively. Shown are the last 3 trials of an HFS-STN conditioning session. The glutamatergic responses are strongly attenuated, GABAergic currents persist. E) Plot of current integrals during individual HFS-STN trials against trial number. The responses are normalized to the current integral during the first train (only cells with integral values >25 pA*s during first train included).