Exo-endocytotic activity during recovery from a brief tetanic stimulation: a role in calcium extrusion?

Synaptic transmission, metabolism of calcium and ultrastructural changes were investigated at the nerve-electroplaque synapse of Torpedo marmorata during and after a brief tetanic stimulation. Calcium was found to accumulate in stimulated tissue as a function of the number of stimuli; it was subsequently expelled during the recovery period. This period was also accompanied by a marked hydrolysis of energy-rich phosphates (ATP and creatine phosphate).