Figure 1.

HD-related differences in tonic GABA action in the striatum. (A) Specimen records of I_Tonic(GABA) from SONs in slices from 1 year old WT and Q175 HD. Experiments in the presence of DNQX (10 μM), APV (50 μM), LY341495 (40 μM); no K⁺ channel block. Graphs on the right: Gaussian fits to all-points histograms derived from 30 s recording periods under control conditions and in the presence of BMI. The difference between the peaks of the fitting curves represents the amplitude of I_Tonic(GABA) as plotted in (B). (B) I_Tonic(GABA) obtained from WT (empty symbols) and HD mice (filled symbols). Note similar results in the two mouse models of HD. Significance levels according to Mann–Whitney-test. (C) Sample traces to illustrate the differential effects of GABA(B) unblocking with CGP (1 μM) in WT and HD. Records under similar conditions as in panel (E). (D,E) Quantification of results for eIPSC amplitude and PPR. Note lack of CGP effect in HD mice and similar results from Q175 and R6/2 WT. Significance levels according to paired t-tests. The asterisks denote the following: ^*p < 0.05, ^**p < 0.01, and ^***p < 0.001.