THE ACTION POTENTIALS OF THE SQUID EYE

Abstract

During light-stimulation 2 action potentials of opposite electrical sign (with regard to a common reference electrode) were recorded from opposite sides of the receptorial layer of the retina of the squid (Loligo pealii). The end of the receptors (i.e., Membrana limitans) became negative whereas the base (i.e., the peripheral side) became positive at the same time. On account of general observations with respect to placement of electrodes as well as on the effect of a proceeding dark-adaptation and intensity-variation, these 2 action potentials are probably due to different processes. The suggestion is supported by observed differential effects of glucose, O2, K, adrenaline and atropine. The effects of these biological agents are compared with the previously studied effects of the same agents on the different components of the frog''s electroretinogram (ERG). The action potentials of the squid eye resemble not only in shape but also in their reactions the PHI (i.e., negative) component of the vertebrate ERG. The identification of PIII with the receptorial action potentials of the squid eye emphasizes the elementary character of the PHI component.