DIFFERENTIAL EXPRESSION OF CALRETININ, CALBINDIN D28K AND PARVALBUMININ THE DEVELOPING HUMAN CEREBELLUM

Three calcium-binding proteins, calretinin, calbindin D28K and parvalb umin, were immunohistochemically localized in the human cerebellum at different developmental stages. Cells positive for calretinin were not detected during early development of the cerebellum until 21 weeks of gestation at which stage weak staining was found in Purkinje and bask et cells of the cortex and in neurons of the dentate nucleus. Both the number of positive cells and the intensity of immunoreactivities were found to increase as the cerebellum became more mature. Calbindin D28 K immunoreactivity was, however, detected early in development at 14 w eeks of gestation. Positive cells were found in Purkinje, basket, stel late and granule cells of the cerebellar cortex and in neurons of fast igial, globose, emboliform and dentate nuclei. The number of positive cells and the staining intensity for calbindin in both the cerebellar cortex and deep nuclei decreased at more advanced developmental stages . At 21-31 weeks of gestation, positive staining was restricted to Pur kinje and basket cells of the cortex. Parvalbumin immunoreactivity was also observed early in development at 14 weeks of gestation. Positivi ty was found in Purkinje, basket and stellate cells of the cerebellar cortex and in neurons of all the deep nuclei, with the highest number of positive cells in the fastigial nucleus followed by emboliform, glo bose and dentate nuclei. As the cerebellum became more mature, both th e number of positive cells and the staining intensity for parvalbumin decreased in the cortex and deep nuclei. The results of the present st udy showed that among the three calcium-binding proteins examined, str ong immunoreactivities for calbindin D28K and parvalbumin were found i n the human cerebellum early in development at 14 weeks of gestation, but there was a decrease in both the intensity and number of positive cells at more advanced stages. In contrast, calretinin positive cells were not detected until 21 weeks of gestation and the immunoreactivity increased as the cerebellum became more mature. A possible correlatio n between the developmentally regulated expression of the calcium-bind ing proteins and expression of different neurotransmitters during deve lopment is discussed. (C) 1997 Elsevier Science B.V.