Figure 3. The decay kinetics of NMDA receptor EPSCs in axotomised motoneurons.

A, examples of EPSCs (6 responses were averaged in both cases) evoked in motoneurons of a 6-day-old (PND 6) and an 11-day-old animal (PND 11). The decay of NMDA receptor EPSCs was fitted by a double exponential function with the time constants and their relative amplitude indicated. Note the differences in the decay kinetics of NMDA receptor EPSCs. EPSCs were recorded from motoneurons at a holding potential of +40 mV in the presence of 1 mm Mg²⁺ and 5 μm CNQX. B, the graphs indicate the fast component (τ_fast), the slow component (τ_slow) and the relative contribution of the fast component (A_fast) of the NMDA receptor EPSC in axotomised motoneurons. The values of the fast and slow components of NMDA receptor EPSCs in motoneurons of PND 6–11 significantly decreased as a function of time after axotomy (one-way ANOVA; P_fast = 0.0015; P_slow = 0.0035); however, the relative contribution of these components was not significantly changed (P = 0.185).