The Journal of neuroscience : the official journal of the Society for Neuroscience
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Photoreceptors of the Limulus lateral eye shed their light-sensitive membranes (rhabdoms) in a burst early each morning when the animal is maintained in natural lighting. This shedding burst produces a cloud of multivesicular bodies which coalesce and migrate away from the rhabdom. Within 24 hr, these gradually collapse to combination bodies and ultimately to lamellar bodies. ⋯ Within 15 min of light onset the area of photosensitive membrane decreases by about 70%, and within an hour the rhabdom returns to essentially its preburst size. At other times in the diurnal light cycle, the size of the rhabdom undergoes significant variations which are not abolished by blocking the efferent input. Apparently the daily burst of shedding overlays a second cycle of membrane metabolism that is not controlled by efferent optic nerve activity.