Long-lasting decrease in the crayfish giant motoneuron soma excitability induced by Ca2+ influx

After a single Ca-dependent action-potential or a 300 ms clamp pulse to 0 mV in the motor giant somata of the crayfish abdominal nerve cord, a decrease in input resistance, an afterhyperpolarisation and a shortening of the test action potentials were observed during 10-15 min. These effects were due to a novel type of long-lasting outward current, triggered by a single influx of Ca2+, resistant to TEA+ and blocked by Ba2+.