Biomedical subjects

Mu Zhang

Publications and source records attributed to Mu Zhang.

5 recordsLinked to original sources

PubMed2004

Nitric oxide spatial distribution in single cultured hippocampus neurons: investigation by projection of reconstructed 3-D image and visualization technique.

Recent studies have revealed a non-homogeneous distribution of nitric oxide synthase (NOS) in neurons. However, it is not yet clear whether the intracellular distribution of NOS represents the intracellular nitric oxide (NO) distribution. In the present study, software developed in our laboratory was applied to the reconstructed image obtained from confocal slice images in order to project the 3-D reconstructed images in any direction and to cut the neuron in different sections. This enabled the spatial distribution of NO to be visualized in any direction and section. In single neurons, NO distribution was seen to be heterogeneous. After stimulation with glutamate, the spatial changes in different areas of the neuron were different. These findings are consistent with immunocytochemical data on the intracellular localization of nNOS in hippocampus neurons, and will help to elucidate the specificity of nitric oxide signaling. Finally, the administration of SNAP and L-NAME was used to examine DAF-2 distribution in the neurons. The results showed this distribution to be homogenous; therefore, it did not account for the NO distribution results.

Animals↗

PubMed2004

Nitric oxide imaging in neurons using confocal microscopy.

The instability and low concentration of nitric oxide (NO) in specimens make it difficult to be detected directly. In this chapter, a method for imaging nitric oxide using laser scanning confocal microscopy (LSCM) is presented. A cultured hippocampal neuron is dyed with DAF-2 and observed under a Zeiss LSM 510 laser scanning confocal microscope. A 488-nm laser power is applied as excitation and the emission light from the labeled nitric oxide in the neuron is detected. In this way, nitric oxide is imaged and its intracellular kinetic change is monitored. Furthermore, image processing and visualization techniques are employed to help analyze the image data.

Animals↗

PubMed2003

Inhibitory effect of jujuboside A on glutamate-mediated excitatory signal pathway in hippocampus.

Jujuboside A (JuA) is a main component of jujubogenin extracted from the seed of Ziziphus jujuba Mill var spinosa (Bunge) Hu ex H F Chou (Ziziphus), which is widely used in Chinese traditional medicine for the treatment of insomnia and anxiety. Previously, we reported the inhibitory effects of JuA on hippocampal formation in vivo and in vitro, the present study was carried out to examine the effects of JuA on glutamate (Glu)-mediated excitatory signal pathway in hippocampus. Microdialysis coupled with high-performance liquid chromatography (HPLC) was used to monitor the changes of Glu levels in the hippocampus induced by penicillin sodium, or a mixture of penicillin sodium and JuA. The results showed that penicillin increased the hippocampal Glu concentration (p < 0.01) and a high dose of JuA (0.1 g/L) significantly blocked penicillin-induced Glu release (p < 0.05). Moreover, the effect of JuA on intracellular Ca2+ changes after the stimulation by Glu was studied in cultured hippocampal neurons with confocal laser scanning microscope (CLSM). It was found that Glu (0.5 mM) induced an intracellular [Ca2+]i increase (p < 0.01), and JuA significantly inhibited the Glu-induced Ca2+ increase. The calmodulin (CaM) antagonist trifluoperazine (TFP) showed a similar inhibitory effect as JuA. These observations suggested that JuA has inhibitory effects on Glu-mediated excitatory signal pathway in hippocampus and probably acts through its anti-calmodulin action.

Animals↗

PubMed2003

BRITTLE CULM1, which encodes a COBRA-like protein, affects the mechanical properties of rice plants.

Plant mechanical strength is an important agronomic trait. To understand the molecular mechanism that controls the plant mechanical strength of crops, we characterized the classic rice mutant brittle culm1 (bc1) and isolated BC1 using a map-based cloning approach. BC1, which encodes a COBRA-like protein, is expressed mainly in developing sclerenchyma cells and in vascular bundles of rice. In these types of cells, mutations in BC1 cause not only a reduction in cell wall thickness and cellulose content but also an increase in lignin level, suggesting that BC1, a gene that controls the mechanical strength of monocots, plays an important role in the biosynthesis of the cell walls of mechanical tissues.

Amino Acid Sequence↗

PubMed2003

The influence of oxygen-glucose deprivation on nitric oxide and intracellular Ca(2+) in cultured hippocampal neurons.

Nitric oxide (NO) was speculated to play an important role in the pathophysiology of cerebral ischemia. In this study, the effect of oxygen-glucose deprivation (OGD) on the cellular production of NO was investigated in cultured hippocampal neurons. Intracellular Ca(2+) was also detected as its closely relationship with NO. The generation of NO and changes in intracellular Ca(2+) were evaluated using confocal laser scanning microscopy with diaminofluorescein diacetate (DAF-2 DA), an NO probe, and Fluo-3, a Ca(2+) probe respectively. Extracellular glutamate level was also measured by HPLC with fluorescence detection. Results showed that OGD induced an increase in NO production and intracellular Ca(2+) concentration ([Ca(2+)](i)), the rise of DAF-2 and Fluo-3 fluorescence intensity was about 160% and 270% respectively; an increase of about 100% in glutamate level was observed after 20 min of OGD. NMDA inhibitor MK-801 significantly reduced the OGD-induced elevation of [Ca(2+)](i) and NO, DAF-2 and Fluo-3 fluorescence intensity uptake was inhibited by 69% and 74% respectively. The increase in NO production was also attenuated by extracellular Ca(2+) elimination and calmodulin (CaM) antagonist trifluoperazine dose-dependently. These results indicated that NO production increased during oxygen-glucose deprivation, and was greatly modulated by glutamate release, intracellular Ca(2+) change and Ca(2+)-CaM pathway.

Animals↗