L-Aspartic acid induces a region of negative slope conductance in the current-voltage relationship of cultured spinal cord neurons.

Individual murine spinal cord neurons were grown in dissociated tissue cultures. Using either one or two conventional intracellular microelectrodes neurons were voltage-clamped and current-voltage (I-V) curves were constructed using command pulses. L-Aspartic acid was then applied and I-V curves repeated in the presence of this excitatory amino acid. L-Aspartic acid induced a region of negative slope conductance (RNSC) in the steady-state I-V relationships of these neurons. Such a RNSC accounts for the apparent reduction of conductance in response to excitatory amino acids and its instability likely contributes to the electrogenesis of bursting in central neurons.