This content is PDF only. Please click on the PDF icon to access.
Abstract
The pre- and postnatal development of Müllerian cells of the rabbit retina were studied with light and electron microscopy. The first differentiation of the Müllerian cells appears as the formation of smooth-surfaced endoplasmic reticulum in the innermost (vitread) portion of the retina, on the fourteenth day of gestation. Ganglion and amacrine cells differentiate in the vitread portion of the neuroblastic layer during the eighteenth to twenty-sixth days of gastation, by which time smooth-surfaced endoplasmic reticulum is scattered throughout the inner processes of the Müllerian cells. During the late prenatal period, bipolar and horizontal cells are formed and glycogen particles, characteristic of the mature Müllerian cell, appears scattered throughout their cytoplasm. Mitochondria become concentrated in the apices of these cells, near the external limiting membrane. After birth, the major changes in Müllerian cells are elongation of their microvillous processes, lateral cytoplasmic extensions, and rearrangement of their nuclei. The intercellular extensions of Müllerian cells grow in the outer and inner plexiform layers in these postnatal stages. Their nuclei, which had been located at different levels of the inner nuclear layer at birth, become arranged in the innermost, or second-innermost zone of this layer, external to the amacrine cells. The Müllerian cells are complete by the end of the third postnatal week. Our observations suggest that their synthetic activity occurs in the postnatal period.