Cellular decay in the rat retina during normal post-natal development: a preliminary quantitative analysis of the basic endogenous rhythm.

The diurnal variation in the appearance of cell death in the rat retina during postnatal development was investigated. The frequency and the morphology of the necrotic cells and the mitotic figures were studied by light and electron microscopy at various stages of ontogenesis and at specified times during each day. Preliminary results show that there is a varying exponential behaviour of mean necrosis-densities at certain periods each day. This chronobiological pattern and the general problems of physiological cellular decay in the developing retina are discussed.