An Investigation of the Electrical "Spike" Potentials Produced by the Sea Lamprey (Petromyzon marinus) in the Water Surrounding the Head Region

Abstract

In the water surrounding the head of Petromyzon marinus electric triphasic spike potentials can be recorded which recur rhythmically at 0.4-second intervals and are synchronous with the externally visible movement of respiration. At a distance of 15 to 20 mm. from the animal, above the eye region, the potentials are from 200–300 μv in an adult lamprey, in fresh water. The electric field produced by these potentials extends several centimeters frontwards of the head depending on experimental conditions and factors now being studied. Posterior to the gill openings the potentials taper off sharply and no spikes could be recorded 50–70 mm. posterior to the last gill opening. The field is symmetrical around the longitudinal axis of the animal under the experimental conditions described. Strychnine and cocaine do not affect the characteristics of the spikes but curare decreases their potential considerably, depending on amounts injected and the condition of the experimental animal. Light conditions do not affect the production of the spikes. The possible function of the electric field for the sea lamprey is discussed.