Potassium ions play a role in the glycine-induced inhibition of rat substantia nigra zona compacta neurones.

Glycine directly inhibits the firing, it hyperpolarizes and/or depolarizes the dopaminergic neurones and increases the membrane conductance. In voltage clamp experiments (near resting potential) either outward and/or inward currents were produced. These actions were present in tetrodotoxin and in 0-calcium-cobalt-treated slices and were antagonized by strychnine. The hyperpolarization depended on the extracellular concentration of potassium and was prevented by cesium diffusion into the cell. Thus potassium ions participate in the glycine mediated inhibition of the firing of substantia nigra zona compacta cells.