X-ray Diffraction from Outer Segments of Visual Cells in Intact Eyes of the Frog

Abstract

X-RAY diffraction patterns have been obtained from the light receptor membranes of frog retinal rod outer segments (of Rana temporaria and pipiens)^1,2 and a one dimensional electron density profile across the membrane has been derived¹. Until now the closest approach to studying the membranes in physiological conditions has been to pass X-rays through the outer segment layer of a strip of retina dissected from an eye and placed in a chilled glucose-supplemented Ringer solution¹. To obtain a higher resolution electron density profile and minimize the possibility of artefact production, I have recorded X-ray diffraction patterns from photoreceptor layers in intact isolated whole eyes and also from eyes in a pithed frog with its heart beating throughout the experiment. Insofar as the respiratory system keeps functioning and the choroid and retina adjacent to the outer segments are intact, this experiment approaches an in vivo study.