The effect of current passage on N-methyl- d-aspartate-induced, tetrodotoxin-resistant membrane potential oscillations in lamprey neurons active during locomotion

Abstract

In lamprey spinal cord neurons, N-methyl-aspartate (NMA) can elicit tetrodotoxin (TTX)-resistant membrane potential oscillations (10–25 mV), that are of similar frequency to those recorded during NMA-induced fictive locomotion before TTX. The frequency of the oscillations was progressively reduced when increasing the amount of hyperpolarizing DC current. Brief de- or hyperpolarizing pulses gave phase-dependent effects on the duration of the oscillation cycle and rhythm resetting. Periodic stimuli could entrain the oscillatory activity. Under normal conditions, these oscillations will be influenced by synaptic activity, leading to an adequate coordination between neurons active during locomotion.