Neurons and glia in the central nervous system can express the key enzymes for the synthesis of neurosteroids .Once the concentration of neurosteroids is high enough , they will exert paracrine effects .Synthesis of neurosteroids declines with age in brain .So does it under stressful circumstances .Recent research reports indicate that the decrease of neurosteroids is associated with the neuronal dysfunction and degeneration in the brain .This paper reviews recent research on the most studied neurosteroids ( for example , dehydroepiandrosterone , pregnenolone and their sulphate esters, progesterone and allopregnanolone ) in affecting neuronal survival , neurite outgrowth and neurogenesis , and the potential roles of these neurosteroids in the treatment of neurodegenerative disease as well .

It was bound to think highly of its teaching reform,because our college has in-creased the recruitment of foreign students since 2006.Based on teachers'English level,foreign students'own qualities,discrepancy between teaching mode as well as proper characteristic of preclinical medicine curriculum,the problems were investigated and the corresponding solutions have been sought in the phase of preclinical medicine.

It is very common that the number of neurons in the brain is progressively decreasing in the neurodegen-erative diseases such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease, etc.Moreover, it is much more important that there is a decline in the neurogenesis of adult brain in such neurodegenerative diseases. In treating neurodegenerative diseases, it is a potential therapeutic modality to promote endogenous neurogenesis in the brain.

To explore the effect of different concentrations of corticosterone (CORT) on primary cultured hippocampal neurons and their Ca2+/CaMK II expression and possible mechanism, the changes of hippocampal neurons were observed in terms of morphology, activity of cells, cell death, concentrations of cytosolic free calcium, and the expression of CaMK II by using MTT assay, flow cytometry, fluorescent labeling of Fura-2/AM and Western blotting after 10(-7), 10(-6) and 10(-5) mol/L of CORT was added to culture medium, The evident effect of 10(-6) and 10(-5) mol/L of CORT on the morphology of hippocampal neuron was found. Compared with control neurons, the activity of the cells was markedly decreased and [Ca2+]i increased in the neurons treated with 10(-6) and 10(-5) mol/L of CORT, but no change was observed in the neuron treated with 10(-7) mol/L of CORT. The death was either by way of apoptosis or necrosis in the cells treated with 10(-6) and 10(-5) mol/L of CORT respectively. The correlation analysis showed that a reverse correlation existed between [Ca2+]i and the expression of CaMK II. Either apoptosis or necrosis occurs in the hippocampal neurons treated with CORT. The increased hippocampal [Ca2+]i is both the result of CORT impairing the hippocampal neurons and the cause of the apoptosis of hippocampal neurons and the decreased CaMK II expression.
Animals ; Apoptosis ; drug effects ; Calcium ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases ; biosynthesis ; genetics ; Cells, Cultured ; Corticosterone ; pharmacology ; Hippocampus ; cytology ; enzymology ; Neurons ; cytology ; Rats ; Rats, Wistar