The research and application of astrocytes have developed into a frontier of neuroscience in recent years.This review describes the shapes,regulation mechanism and function of astrocytes,and their relation to neurological diseases.Astrocytes play an important role in growth and reparation of the nervous system.

The impairment of learning and memory function in the central nervous system(CNS)is one of the main features of aging and Alzheimer' s disease (AD). Many experimental results have showed that long- term memory(LTM) is related to long- term potentiation(LTP) and long- term depression (LTD). They intluenee each other. The relationship between LTP and LTD is complex. Therefore, it is important to study the learning and memory mechanism from LTP、LTD and gene expression in the CNS.

AIM: To observe the effects of IBMX on cGMP production in gerbil hippocampus after recirculation following ischemia. METHODS: Bilateral occlusion of common carotid arteries and immunofluorescent staining methods in gerbil hippocampal tissue slice were used. RESULTS: Recirculation following ischemia caused a rise in hippocampus cGMP concentration. IBMX increased cGMP production. cGMP positive cells mainly distributed in rediatum layer and molecular layer in the CA_1 subfield. CONCLUSION: IBMX increased cGMP production in gerbil hippocampus after recirculation following ischemia.

This review describes the application of stem cells.Stem cells have proliferating and (multipotential) differentiation properties.Stem cells play an important role in the repair tissue and organs.

The impairment of learning and memory function in the central nervous system(CNS)is one of the main features of aging and Alzheimer's disease(AD).Many experimental results have showed that long- term memory( LTM) is related to long- term potentiation( LTP) and long- term depression(LTD).They influence each other.The relationship between LTP and LTD is complex.Therefore,it is important to study the learning and memory mechanism from LTP、LTD and gene expression in the CNS.

Neuralstemcells (NSCs)maintainthepotentialofproliferationanddifferentiationin nervesystem .TheresearchandapplicationofNSCshavedevelopedintoafrontierofneuroscienceinrecent years .Thisreviewdescribesthespecificity ,contribution ,regulationmechanismandapplicationofNSCs . Neuralstemcellsplayanimportantroleinthenervoussystemofgrowthandreparation . [

Glioma is the most frequent type of intracranial tumors,which is always associated with epilepsy.The type,location and pathological grade of glioma is closely related to incidence and efficacy of epilepsy.Recent re search shows that glioma and the factors around it may effect on the balance between excitation and inhibition system of brain.The detailed pathogenesis of epilepsy remains to be studied.

The purpose of the present work is to observe cGMP positive cells after cerebral ischemia-reperfusion in the gerbil hip-pocampus. Immunofluorescent methods were used in gerbil hippocampal tissue slices. The results showed that after cerebral is-chemia cGMP synthesis in the CAi-a subfields was increased, cGMP positive cells were distributed mainly in CA1 subfield. Mostof cGMP positive cells were astrocytes. The number of small round cGMP positive cells were increased after recirculation follow-ing ischemia in the dentate gyrus. These results indicate that after cerebral ischemia cGMP synthesis was increased in the CA1-asubfield, It is possible that astrocytes play an important role in the regulation of metabolism in the early stage after ischemia-reperfusion.

Aim To observe the effect of sodium nitrop russide (SNP)on glial fibrillary acidic protein(GFAP) synthesis in the gerbil hippocampus. Method lmmunofluorescent histochemical staining method was used. Result SNP increased GFAP synthesis in rediatum layer,molecular layer and dentate gyrus.There were not GFAP positive cells in rediatum layer and mol ecular layer.Number of GFAP positive cells related to dose of SNP.Conclu sion SNP increased GFAP synthesis.

AIM To observe the effects of L NNA on glial fibrillary acidic protein (GFAP) production in the gerbil hippocampus after recirculation following ischemia. METHODS Both vessels occlusion and immunofluorescent methods in gerbil hippocampal tissue slices incubated in vitro were used. RESULTS Recirculation following ischemia led to a rise on GFAP concentration in the hippocampus. GFAP positive cells mainly distributed in rediatum layer and molecullar layer in the hippocampus, L NNA decreased GFAP synthesis. CONCLUSION L NNA is a strong inhibitor of nitric oxide synthase(NOS). It is possible that the role of endogenous NO mediated GFAP synthesis is inhibited by L NNA.