Cytoarchitecture and immunolocalisation of BDNF in the somatosensory cortex of the African grasscutter (Thryonomys swinderianus – Temminck, 1827)

Development of cerebral cortex depends on positioning of its neurons, which occurs in an organised, layer-specific pattern. This paper describes the histological features of the African grasscutter somatosensory cortex on foetal and postnatal periods and immunolocalise Brain Derived Neurotrophic Factor (BDNF) on the postnatal periods. Brain samples from explanted foetuses on foetal day 90, neonates, juveniles and adults on postnatal days 3, 72 and 450, respectively, were used for the study. Cresyl fast violet stain was employed for the cytoarchitectural study, while anti-BDNF antibody was used for immunohistochemical analysis. Lamina organization of the somatosensory cortex was evident on foetal day 90, but continued post-mitotic neurone migration from the ventricular zone to the cortical plate was observed. The molecular layer was thin and acellular on postnatal day 3, had few neurons on postnatal day 72 and increased thickness on postnatal day 450. There was evidence of increased amount of choroid plexus in the lateral ventricle on postnatal day 450. Mild immunoreactivity to BDNF was observed in the molecular layer on postnatal day 3 and non-reactivity on days 72 and 450. Strong immunoreactivity to BDNF was observed in the internal pyramidal layer on postnatal days 3 and 450, and moderate immunoreactivity on day 72. Cell nucleus of immunoreactive neurones did not express BDNF. The functional significance of these findings was discussed..