Distribution of Calretinin-immunoreactive Unipolar Brush Cells in Ataxic Mutant Pogo Mice Cerebellum / 대한해부학회지

Unipolar brush cells (UBCs) are a class of putative interneurons found in the granular layer of mammalian cerebellum and dorsal cochlear nucleus. The unipolar brush cells (UBCs), as with granular cells, which receives afferent synaptic input from extrinsic mossy fiber and whose axons branch in the granular layer and establish a system of cortex-intrinsic mossy fibers, which synapse with granule cells and other UBCs. In general, UBCs have been identified most readily by their expression of the calcium-binding protein, calretinin. The purpose of this study was to provide information about UBCs distributions of the new ataxic animal model, pogo mouse cerebellum using anti-calretinin immunohistochemistry, immunofluorescence and its effect on calcium homeostasis. Through the examination of calretinin immunohistochemistry and immunofluorescence, we observed that many calretinin immunoreactive UBCs were distributed widely throughout the lobules IX and X of the granular layer of both group. But, we found the number of calretinin immunoreactive UBCs of ataxic pogo (pogo/pogo) mouse was decreased and distribution pattern was altered, compared to control mouse. This result also suggest that reduced calretinin expression may effect on cerebellar Ca2+/-homeostasis, and it may in turn, explain the impaired motor coordination found in the ataxic pogo mice.

Distribution of trkA in cerebral cortex and diencephalon of the mongolian gerbil after birth

TrkA is essential components of the high-affinity NGF receptor necessary to mediate biological effects of the neurotrophins NGF. Here we report on the expression of trkA in the cerebral cortex and diencephalon of mongolian gerbils during postnatal development. The expression of trkA was identified by immunohistochemical method. In parietal cortex and piriform cortex, higher levels of trkA-IR (immunoreactivity) were detected at 3 days postnatal (P3) and at P9. Although trkA was not expressed till P3 in the parietal cortex, it was detectable at birth in the piriform cortex. Several regions, such as Layers I, IV & VI, did not show much expression. Layer I showed especially weak labeling. In the hippocampus, thalamus, and hypothalamus, higher levels of trkA-IR were detected at P6 and P12 than earlier days. But trkA was not expressed at birth in the hippocampus, at P3 in the reticular thalamic nucleus (Rt), or neonatally in the dorsomedial hypothalamic nucleus (DM). This data shows that expression of trkA is developmentally regulated and suggests that high affinity neurotrophin-receptors mediate a transient response to neurotrophines in the cerebral cortex and diencephalon during mongolian gerbil brain ontogeny.