Response Of The Rats Astrocyte In The Raphe Nucleus To Sleep Deprivation And Its Relationship With Neurons

Astrocytes is important component in CNS. Recently, we found the interaction and intercommunication between neurons and astrocytes. Astrocyt can modulate the excitatory activaty of the neurons through changing the concentration of extracellular neural active substance or controlling the microenvironment. As known,glial fibrillary acidic protein (GFAP) is marker of the activation of astrocyte.The aim of this study is to investigate the reaction of astrocyte of the raphe nucleus following sleep deprivation and its interaction with neurons in regulation of sleep.Part one : Expression of GFAP protein in the raphe nucleus of rats after sleep deprivation.Methods: Sprague-Dawley rat's sleep was deprived by housing them on the small platforms over water. Control rats were housed in the normal cage on the large platform over water. The effect of SD on the expression of GFAP protein was investigated by immunocytochemistry. The durations of sleep deprivation were 3, 6, 12, 24, 48, 72, 96 hours, respectively. Result: Sleep deprivation resulted differential expression of Fos and GFAP protein at different fields of raphe nucleus. FOS and GFAP increased significantly in dorsal raphe nucleus raphe pallidus nucleus. With prolonged sleep deprivation the change of FOS and GFAP was not synchronized. Conclusion: Sleep deprivation may affect GFAP protein expression, astrocyte involved in the regulation of sleep.Part two: Response of the rats astrocyte in raphe nucleus to sleepdeprivation and sleep recovery and its relationship with neuronsMethods: Two groups of Sprague-Dawley rats sleep were deprived by housing them on the small platforms over water for 12h. After that experimental group rats sleep 3h. Control group was housed in the normal cage on the large platform over water. The effects of sleep deprivation and sleep recovery on the expression of GFAP and Fos protein were investigated by immunocytochemistry. Result: Sleep deprivation resulted in increasing expression of GFAP protein in raphe nucleus . The main field was dorsal raphe nucleus Experimental group rats,expression of GFAP protein decreased significantly after sleep 3h. The change of GFAP expression was similar to Fos protein. Conclusion: Sleep deprivation and sleep recovery affect GFAP protein expression, both astrocytes and neurons involve in regulation of sleep .Part three: Response of the rats astrocyte in the raphe nucleus to sleep deprivation and its relationship with neurons: fos, GFAP and 5-HT triple immunohistochemical staining.Methods: Same as part two. The expression of Fos, GFAP and 5-HT in the raphe nucleus was studied by triple method, combining anti GFAP Fos and 5-HT immunocytochemistry staining. Result: Expression of Fos and GFAP in the raphe nucleus increased after sleep deprivation . The main field was dorsal raphe nucleus After sleep 3h, the expression of Fos and GFAP decreased significantly. The distribution of positively stanied GFAP in astrocyt is similar to Fos in neurons. Singly labeled neurons by Fos and 5-HT,or doubly labeled neurons by Fos and 5-HT in dorsal raphe nucleus arounded by GFAP positive neurons were found and formed three kinds of complex like structures(Fos+GFAP+; 5-HT+GFAP+; Fos+5-HT+GFAP+). Conclusion: The present results indicate that astrocyte is sensitive to sleep deprivation and sleep recovery. Results demonstrate both astrocytes and neurons involve in the regulation of sleep .By the research, we can find out that: with prolonged sleepdeprivation, the reaction of astrocyt is dissynchronized with the neurons; the expression of GFAP protein keep in a high level. But after sleep, the expression of GFAP protein decreased significantly. It synchronize with the reaction of neurons in the raphe dorsal neucleus. The astrocyte and neurons in the raphe dorsa neucleus may be combined together as a complex in the regulation of sleep.The other cells in raphe neucleus in the regulation of sleep is not clear.They may not involve in the regulation of sleep directly.