Figure 1. Voltage-clamp recording of glycine-induced current in neurons of acute SCN slices.

A, locally applied glycine at concentrations between 10 μm and 3 mm for 5 s elicits outward currents at a holding potential of 0 mV. B, dose–response relationship for glycine. Each point represents the average of 4 to 14 SCN neurons. The sigmoidal curve is fitted using the Hill equation showing a maximal current at a concentration of 10 mm and an EC₅₀ of 780 μm. C, extracellular recordings show an inhibition of the spontaneous firing rate in response to glycine application. With increasing concentrations the duration of spike inhibition increases. D, applications of the glycine receptor agonists β-alanine (1 mm) and taurine (10 mm) induce currents with similar characteristics to glycine-induced currents when applied to the same cell (n = 13).