Glycine receptors are ligand gated ion channels, which, when activated, reduce firing. Ethanol is a positive allosteric modulator of the glycine receptor (Farley and Mihic, 2015). Four subunits, α1, α2, α3 and β, had decreased expression, which may compensate for the positive modulation by ethanol. Glrb (encoding the gly-B receptor) is the most abundantly expressed glycine receptor in the PAG, and has been implicated in hypo-nociception (Martins et al., 2008), thus the reduction in this receptor could increase nociception. Expression of the glycine reuptake transporter gene, Slc6a5, was also decreased, which may moderate the effect.
