[Morphometric analysis of epitheliocytes in the choroid plexus of brain ventricles in rat ontogenesis].

Light and dark epitheliocytes of choroid plexus were studied by morphometric methods in lateral and III ventricle of rat's brain during development. Investigations were performed on semithin sections using point-counting method with combined ocular test-system for linear and planimetric measurements. The results obtained suggest that light and dark choroid plexus epitheliocytes complete their differentiation by postnatal day 30. The profile area of the dark cells is smaller than that of the light cells and this difference persists up to the age of 22 months. The proportion of dark epitheliocytes was found to increase gradually during development and to exceed that of the light cells at 13 months, increasing continuously up to the age of 22 months. Changes of morphometric parameters of rat's brain ventricle epitheliocytes during development suggest that dark and light cells are varieties of the single basic cell type with possible functional differentiation that starts on postnatal day 17 and continues up to 22 months.