PT  - JOURNAL ARTICLE
AU  - F. Clifford Rodgers
AU  - Ewa D. Zarnowska
AU  - Kurt T. Laha
AU  - Elif Engin
AU  - Anja Zeller
AU  - Ruth Keist
AU  - Uwe Rudolph
AU  - Robert A. Pearce
TI  - Etomidate Impairs Long-Term Potentiation <em>In Vitro</em> by Targeting α5-Subunit Containing GABA<sub>A</sub> Receptors on Nonpyramidal Cells
AID  - 10.1523/JNEUROSCI.0315-15.2015
DP  - 2015 Jul 01
TA  - The Journal of Neuroscience
PG  - 9707--9716
VI  - 35
IP  - 26
4099  - http://www.jneurosci.org/content/35/26/9707.short
4100  - http://www.jneurosci.org/content/35/26/9707.full
SO  - J. Neurosci.2015 Jul 01; 35
AB  - Previous experiments using genetic and pharmacological manipulations have provided strong evidence that etomidate impairs synaptic plasticity and memory by modulating α5-subunit containing GABAA receptors (α5-GABAARs). Because α5-GABAARs mediate tonic inhibition (TI) in hippocampal CA1 pyramidal cells and etomidate enhances TI, etomidate enhancement of TI in pyramidal cells has been proposed as the underlying mechanism (Martin et al., 2009). Here we tested this hypothesis by selectively removing α5-GABAARs from pyramidal neurons (CA1–pyr–α5–KO) and comparing the ability of etomidate to enhance TI and block LTP in fl–α5 (WT), global–α5–KO (gl–α5–KO), and CA1–pyr–α5–KO mice. Etomidate suppressed LTP in slices from WT and CA1–pyr–α5–KO but not gl–α5–KO mice. There was a trend toward reduced TI in both gl–α5–KO and CA1–pyr–α5–KO mice, but etomidate enhanced TI to similar levels in all genotypes. The dissociation between effects of etomidate on TI and LTP in gl–α5–KO mice indicates that increased TI in pyramidal neurons is not the mechanism by which etomidate impairs LTP and memory. Rather, the ability of etomidate to block LTP in WT and CA1–pyr–α5–KO mice, but not in gl–α5–KO mice, points toward α5-GABAARs on nonpyramidal cells as the essential effectors controlling plasticity in this in vitro model of learning and memory.