Fig. 4

Hippocampal cells mIPSC kinetics patterns for GABA_AR subtypes in CIE rats and α4KO mice. A: mIPSC sample traces of CIE- vs. CIV-treated rats and α4KO and WT mice in hippocampal DG cells. B: Averaged mIPSC shape patterns detected by DataView revealed 3–4 relatively abundant distinct templates. In CIV, mIPSC patterns ‘a’, ‘c’, and ‘d’ were detected. Pattern ‘a’ is a standard shape, typical rise and decay kinetics; patterns ‘c’ and ‘c’ are slow rise-slow decay patterns correlated in abundance (not shown here) with α2 subunit subtypes. Three patterns of mIPSCs were also detected in CIE, but the ‘a’ pattern was not seen in CIE, and replaced by the slower decay pattern ‘b’. See text for interpretation that ‘a’ is mainly α1 and ‘b’ is mainly α4 subunit subtypes (as in Liang et al., 2006). Patterns of mIPSCs in WT and α4KO mice are similar to CIV rats, with peaks ‘a’, ‘c’, and ‘d’. However, the abundance of pattern ‘d’ was increased in CIE relative to CIV and in the α4ko mouse relative to WT. Since the CIE but not CIV, and a4KO mouse but not WT exhibited EtOH-enhanced mIPSCs, we examined recordings of these four animal groups with 50 mM EtOH (E50, dashed line) compared to without EtOH (E0, solid line) in the recording chamber. Peak pattern ‘a’ was not significantly enhanced by EtOH, but ‘b’, ‘c’, and ‘d’ were enhanced. Peak ‘b’ in CIE correlates with up-regulated α4, and is not seen in the α4KO mouse. Peak ‘d’ is up-regulated in both CIE rat and α4KO mouse, as is the α2 subunit surface expression, and peak ‘d’ has slow kinetics consistent with the α2 subunit subtypes. Its increase in abundance correlates with the increased average stimulation by EtOH in the recording chamber for both CIE and α4KO. Reproduced from Lindemeyer et al. [30] with permission