Emergence of c-Fos protein in the brain after hypergravity stimulation : From mouse to medaka

In rodents, the immediate-early genes serve as useful neurobiological tools for mapping brain activity induced by gravity changes. In this study, we have examined brain activity related to gravity perception of medaka (Oryzias latipes) by use of c-fos expression. Fish were continuously exposed to 3G hypergravity by centrifugation.The distribution of its transcripts within brains was analyzed by an in situ hybridization method. The 3G-treated medakas displayed c-fos mRNA positive cells in their brain regions, which are related to vestibular function. Using the immunohistochemistry technique, the distribution and number of cells positive for c-Fos proteins were studied. The results showed that wild-type and mutant strain (ha) respond differently to 3G exposure both quantitatively and qualitatively.