Fig. 3.

Genetic depletion of GBR1 abolishes the -dependent mGluR1 sensitization. (A and B) Dose–response relations of DHPG-evoked inward currents in Purkinje cells derived from the WT [GBR1(+/+)] and GBR1-KO [GBR1(-/-)] littermates. CaCl₂ (2 mM) in the saline. V_hold, -70 mV. (A) Each set of superimposed traces indicates the sample responses of a cell to 0.05 and 500 μM DHPG (thick bar). (Calibration bars, 10 s and 50 pA.) (B) Plots summarize the dose–response relations from five to eight cells per point. ^* and ^**, P < 0.05 and P < 0.01 between the WT and GBR1-KO cells (rank sum test), respectively. (C and D) Functional expression of GABA_BR in the WT and GBR1-KO Purkinje cells tested by monitoring the GABA_BR-operated inwardly rectifying K⁺ currents (see Fig. 4E). V_hold, -90 mV. E_K, -57.6 mV. (C) Each trace indicates a sample response to 3 μM baclofen (thick bars). (Calibration bars, 10 s and 100 pA.) (D) Plots summarize the quasi-steady-state amplitudes of the baclofen-induced currents. ^**, P = 0.0056, t test.