General Architecture

Figure 2.

 A view of the cartoon representation

 of glycine bound GlyR viewed parallel to the

 membrane. An individual subunit shown in 

blue with bound glycan’s shown in red

The receptor itself is a ligand-gated ion pore which shows pentametric symmetry around the pore axis. Similarly to other Cys-loop receptors, GlyR has an urn-like shape (figure 1,2).

Within the central nervous system (CNS), Glycine is the primary inhibitory transmitter, causing ion pore dilation upon binding of GlyR, allowing for passage of chloride ions, which results in the hyperpolarization of the cell-membrane potential – causing an inhibitory postsynaptic potential (IPSP). Strychnine is a toxic alkaloid that actively competes for GlyR with agonist glycine, both interacting with the same intersubunit, conserved neurotransmitter binding site. Strychnine binding causes pore closure and blockage of chloride ion permeation. Alternatively, monocyclic lactone ivermectin acts as an allosteric regulator - decreasing conductance and regulating hyperpolarization of the cell membrane potential.