Distinct patterns of expression and regulation of GABA A receptors containing the δ subunit in cerebellar granule and hippocampal neurons

Neuronal plasticity is achieved by regulation of the expression of genes for neurotransmitter receptors such as the type A receptor (GABA A R) for γ‐aminobutyric acid. We now show that two different rat neuronal populations in culture manifest distinct patterns of GABA A R plasticity in response to identical stimuli. Whereas prolonged exposure to ethanol had no effect on expression of the δ subunit of GABA A Rs at the mRNA or protein level in cerebellar granule neurons, it increased the abundance of δ subunit mRNA and protein in hippocampal neurons. Subsequent ethanol withdrawal transiently down‐regulated δ subunit expression in cerebellar granule neurons and gradually normalized that in hippocampal neurons. These effects of ethanol exposure and withdrawal were accompanied by corresponding functional changes in GABA A Rs. GABA A Rs containing the δ subunit were also distributed differentially in the cerebellar and hippocampal neurons. These findings reveal complex and distinct mechanisms of regulation of the expression of GABA A Rs that contain the δ subunit in different neuronal types.