Building new function into glycine receptors: a structural model for the activation of the glycine-gated chloride channel

1. The glycine receptor chloride channel mediates inhibitory neurotransmission and is a member of the ligand-gated ion channel superfamily, which includes the nicotinic acetylcholine receptor channel. 2. Activation of these channels involves a movement of the pore-lining second membrane-spanning domain with respect to the remainder of the protein. 3. The present review considers the evidence that the loops that connect this domain with the rest of the protein act as crucial components of the channel activation mechanism.