Spontaneous and evoked potentials from dissociated epithelial cells of Hydra

Abstract

ALTHOUGH intracellular recording from excitable cells has a thirty-year history, such recording from coelenterate tissue has only recently been achieved^1–4. Mechanical dissociation of previously separated endodermal and ectodermal epithelial layers of Hydra produces a preparation permitting intracellular recording from identifiable classes of cells (Fig. 1). Elicited and spontaneous potentials occur in the cells of both epithelial layers. We have recorded small rhythmically occurring pulses from endodermal cells with positive resting potentials; large spikes from ectodermal cells with negative resting potentials, and regularly occurring membrane oscillations from both types of cells.