Photoreceptor Potentials of Opposite Polarity in the Eye of the Scallop, Pecten irradians |
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| Authors: | John S McReynolds and A L F Gorman |
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| Institution: | From the Laboratory of Neurophysiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland 20014, the Laboratory of Neuropharmacology, Division of Special Mental Health Research, National Institute of Mental Health, St. Elizabeths Hospital, Washington, D. C. 20032, and the Marine Biological Laboratory, Woods Hole, Massachusetts 02543 |
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| Abstract: | Intracellular recordings were obtained from single visual cells of the scallop, Pecten irradians. Two types of units are found. One type gives a graded, depolarizing response to light and the other a graded, hyperpolarizing response. The depolarizing cells are 2–3 log units more sensitive to light and have a longer latency than the hyperpolarizing type. At high light intensities the depolarizing cells are inactivated while the hyperpolarizing cells maintain their responses. When action potentials are seen they occur during illumination in depolarizing cells ("on" response) and after illumination in hyperpolarizing cells ("off" response). The evidence suggests that the depolarizing responses are from the microvilli-brearing proximal cells, and the hyperpolarizing responses from the ciliary-type distal cells of the retina, and that both responses are directly produced by light. |
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