Characteristics of Pacemaker Oscillations in Aplysia Neurons

Abstract

Slow membrane potential oscillations of 5–50 mV in amplitude were unmasked in "bursting" neurons of Aplysia, following treatment with tetrodotoxin. These oscillations were sensitive to changes in membrane polarization; both the amplitude and period decreased with depolarization and increased with hyperpolarization. The oscillations could be blocked by strong depolarization or hyperpolarization, and the two critical levels or stable states corresponded approximately to −30 mV and −70 mV. The bursting discharge of the intact neuron appears to be caused by such an oscillation, but the effects of spike activity on the oscillator mechanism are still largely unknown.