Fig. 6.

NMDARs expressed in different types of basal ganglia neurons differ in gating kinetics. A,B, Traces of current activated by 10 msec pulses of 100 μm glutamate in nucleated patches and the biexponential function fit to the decay phase (3), shown superimposed with its exponential components (1, 2).A, Patch from a dopaminergic neuron of the substantia nigra pars compacta; τ₁ = 166 msec (64%) and τ₂ = 1158 msec (36%). B, Patch from a globus pallidus neuron; τ₁ = 66 msec (78%) and τ₂ = 356 msec (22%). C, Bar graphs of the average time constants of the predominant fast component (τ₁, top panel) and the slow component (τ₂, bottom panel) of deactivation of NMDARs in the populations of basal ganglia neurons investigated. All data are from nucleated patches. Membrane potential, −60 mV; Na⁺-rich external solution (Mg²⁺-free, 10 μm glycine, and 10 μm CNQX) in all cases.