Figure 5. Axonal iontophoresis of L-aspartate does not evoke NMDAR-mediated Ca²⁺ transients.

(A) Direct iontophoretic application of L-aspartate onto an axon varicosity failed to evoke a Ca²⁺ transient. The amplified record is shown in comparison to that without iontophoresis (each record is an average of several trials). Iontophoresis onto a dendrite of the same cell evoked a Ca²⁺ transient confirming the efficacy of L-aspartate application. (B) Peak Ca²⁺ amplitudes recorded in stellate cell processes versus distance from the axon hillock.