• PNF and Movement
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• 제5권1호
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• pp.57-66
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• 2007

This review discusses the development of muscle receptors, in particular, that of muscle sensory neurons and monosynaptic stretch reflex circuit. The development of muscle sensory neurons and monosynaptic stretch reflex requires a series of steps including expression of neurotrophic transcriptional factors and their receptor. The monosynaptic stretch reflex circuit is unique neuronal circuit system, and highly precise synaptic connection systems. Thus, coordination of sensory-motor function in muscle receptors depend on the expression of distinct classes of molecular cues, and on the formation of selective synaptic connections between sensory-motor neurons and their target muscle. Recent neurotrophic and transcription factor expression studies have expanded our knowledge on how muscle sensory neuron is formed, and how sensory-motor system is developed.

• Applied Microscopy
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• 제26권3호
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• pp.329-348
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• 1996

The prenatal development of lateral motor columns in the lumbar spinal cord was studied by electron microscopy in human embryos and fetuses ranging from 9 mm to 260 mm crown-rump length ($5{\sim}30$ weeks of gestational age). At 9 mm embryo, the lateral motor column were developed from ventro-lateral projection into the marginal layer and composed of primitive neuroblasts. At 20 mm embryo the primitive motor neurons were packed closely together and could readly be distinguished from primitive glioblasts by a presence of large nuclei. The primitive multipolar neurons were observed in lateral motor column at 40 mm fetus. At 80 mm fetus multipolar neurons were characterized by their many dendrites and axons in the vicinity of motor neuron perikarya. At 260 mm fetus, the motor neurons were large and contained all intracytoplasmic structures in the cytoplasm which were also found in mature motor neuron in lateral motor column. The first axo-dendritic synapses found at 40 mm fetus and increased in number throughout fetal development. Axo-somatic synapses with spherical vesicles were first observed at 80 mm fetus. A few axo-somatic synapses were found at next prenatal stages. Axo-dendritic and axo-somatic synapses contained mixed populations of spherical and flattened vesicles by 120 mm fetus. These findings indicate that axo-dendritic synapses develop prior to axo-somatic synapses in the spinal cord during neurogenesis.

• 동의생리병리학회지
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• 제29권5호
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• pp.416-421
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• 2015

This study was performed to comparative investigate the distribution of primary sensory and motor neurons associated with Daereung(PC7) acupoints by using neural tracing technique. A total 16 SD rats were used in the present study. After anesthesia, the rats received microinjection of 6 ㎕ of cholera toxin B subunit(CTB) into the corresponding sites of the acupoints Daereung(PC7), in the human body for observing the distribution of the related primary sensory neurons in dorsal root ganglia(DRGs) and motor neurons in the spinal cord(C3∼T4) and sympathetic ganglia. Three days after the microinjection, the rats were anesthetized and transcardially perfused saline and 4% paraformaldehyde, followed by routine section of the DRGs, sympathetic chain ganglia(SCGs) and spinal cord. Labeled neurons and nerve fibers were detected by immunohistochemical method and observed by light microscope equipped with a digital camera. The labeled neurons were recorded and counted. From this research, the distribution of primary sensory and motor neurons associated with Daereung(PC7) acupoints were concluded as follows. Muscle meridian related Daereung(PC7) controlled by spinal segments of C5∼T1, C6∼T4, respectively.

• 동의생리병리학회지
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• 제16권1호
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• pp.150-153
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• 2002

To elucidate the toxic effect of oxygen free radicals on cultured mouse spinal motor neurons damaged by hydrogen peroxide(H₂O₂)-induced neurotoxicity, we examined the neurotoxicity induced by oxygen radicals by NR assay when cultured spinal motor neurons were grown in the medium containing various concentrations of H₂O₂ for 6 hours. In addition, neuroprotective effects of herb extracts such Rhizoma Gastrodiae(RG), on H₂O₂-induced neurotoxicity in cultured spinal motor neurons were evaluated after cultured spinal motor neurons were preincubated with various concentrations of herb extract, RG for 2 hours before 50uM H₂O₂ for 6 hours. H₂O₂ decreased remarkably cell viability in dose-and time-dependent manner in these cultures, and also herb extract, RG increased cell viability of spinal motor neurons damaged by H₂O₂ in these cultures. From the above results, it is suggested that H₂O₂ was toxic in cultured spinal motor neurons derived from mouse, and RG was effective in blocking the neurotoxicity induced by oxidative stress in these cultures.

• The Journal of Korean Physical Therapy
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• 제13권2호
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• pp.433-444
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• 2001

This review highlights the ontogenesis and the differentiation of motor neuron in spinal cord, and introduce the survival motor neuron(SMN) which is associated with growth and survival of motor neurons. The differentiation of floor plate cells and motor neurons in the vertebrate neural tube appears to be induced by signals from the notochord. This signal is Sonic hedgehog(Shh). The early development of motor neurons involves the inductive action of Shh. The SMN gene is essential for embryonic viability. SMN mRNA is also expressed in virtually all cell types in spinal cord, including large motor neurons. The SMN protein is involved in RNA processing and during early embryonic development is necessary fer cell survival. Two SMN genes are present in 5q 13 in humans: the telomeric gene(SMNt), which is the SMA-determining gene, and the centromeric analog gene(SMNc). The majority of transcripts from the SMNt gene are full length but, major transcripts of the SMNc gene have a high degrees of alternative splicing and tend to have little or no exon 7. The SMN is involved in the RNA processing(the biogenesis of snRNPs and pre-mRNA splicing), the anti-apoptotic effects, and regulating gene expression.

• 동의생리병리학회지
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• 제32권1호
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• pp.30-34
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• 2018

This research was practiced to comparative investigate the distribution of sensory and motor neuron linkaged with Yangji(TE4) by using neural-tracer technology. A total 16 S-D rats were used in the present research. After anesthesia, the rats received micro-injection of $6{\mu}{\ell}$ of cholera toxin B subunit(CTB) into the relation positions of the Yangji(TE4), in the human body for observing the distribution of the linkaged sensory neurons in dorsal root ganglia(DRGs) and motor neurons in the spinal cord(C3~T4) and sympathetic ganglia. 3 days after the micro injection, the rats were anesthetized and transcardially perfused saline and 4% paraformaldehyde, followed by routine section of the DRGs, sympathetic chain ganglia(SCGs) and spinal cord. Marked neurons and nerve fibers were detected by immunohistochemical method and observed by light microscope. The marked neurons were recorded and counted. From this study the distribution of primary sensory and motor neurons linkaged with Yangji(TE4) were concluded as follows. Yangji(TE4) dominated by spinal segments of C5~T1, C6~T4, individually.

• 대한한의학방제학회지
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• 제7권1호
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• pp.131-141
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• 1999

In order to eludidate the mechanism of oxidative stress in cultured spinal motor neurons damaged by oxygen free radicals, cytoxicity was assesed by MTT assay and NR assay after spinal motor neurons from mouse were cultured in media containing various concentrations of xanthine oxidase(XO) and hypoxanthine(HX) for 3 hours. In addition, neuroprotective effects of several herb extracts on oxidant-induced neurotoxicity were examined in these cultures, compared with nerve growth factors such as basic fibroblast growth factor(bFGF). XO/HX decreased cell viability in dose- and time dependent manners on cultured mouse spinal motor neurons, and MTT50 and NR50 values were measured at 20mU/ml XO and 0.1mM HX for 3 hours in these cultures. bFGF significantlt increased cell viability. In neuroprotective of herb extracts, Epimedium Koreanum Nakai(EK) and Alpinia oxphylla Mig(IJI) was very effective in the prevention of the neurotoxicity induced by XO/HX in cultured mouse spinal motor neurons. From the above results, it is suggested that XO/HX shows toxic effect in cultured mouse spinal motor neurons and selective herb extracts such as Epimedium Koreanum Nakai(EK) and Alpinia oxphylla Mig(IJI) were very effective in the increase of cell viability against the neurotoxicity induced by oxygen radicals in these cultures.

• 동의생리병리학회지
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• 제16권2호
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• pp.262-266
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• 2002

In order to elucidate the mechanism of cytotoxic effect of oxygen radicals on cultured mouse spinal motor neurons, the neurotoxicity induced by hydrogen peroxide(H₂O₂) was evaluated by MTT assay. The neuroprotective effect of Rhizoma Gastrodiae(RG) against H₂O₂-mediated neurotoxicity was also examined in these cultures by SRB assay. The results were as follows : The value of lethal concentration 50(LC50) of H₂O₂ was estimated at a concentration of 30 uM in these cultures. Cell viability of cultured mouse spinal motor neurons was remarkably decreased by H₂O₂-induced neurotoxicity in a dose- and time-dependent manner. RG was remarkably effective in blocking the neurotoxicity induced by H₂O₂ at a concentration of 120 μM as determined by SRB assay. From above the results, it is suggested that H₂O₂ induce neurotoxicity, and the selective herbal extracted RG was very effective in blocking H₂O₂-mediated neurotoxicity on cultured mouse spinal motor neurons.

• The Journal of Korean Physical Therapy
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• 제23권2호
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• pp.45-52
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• 2011

Purpose: The purpose of this study was to investigate the effect of electroacupuncture on NeuN expression in ventral horn motor neurons of spinal cord, changes in pain thresholdchanges in motor function in rats with partially dissected sciatic nerves. Method: A total of 120 male Sprague-Dawley rats were randomly divided into two groups, a control group and a group administered electroacupuncture at ST36, LI11 and SP9 with 120 Hz and 0.5 mA. Animals were sacrificed on days 1, 3, 7, 14 and 28 after nerve injury (the sciatic nerve was partially dissected). The pain threshold was recorded by an Analgesia? meter and a BBB? score was calculated for motor function. After preparing lumbar spinal cord slide sections, they were immunostained with NeuN antisera (1:2,500). Results: The numbers of NeuN immunoreactive neuronsin the electroacupuncture group was increased compared to the control group. The numbers of NeuN immunoreactive neurons on days 14 and 28 day were different (p<0.05), as were the numbers on days 3 and 7 (p<0.01). The pain threshold BBB score for the electroacupuncture group was higher than for controls. Conclusion: The increase in pain threshold, BBB-score and number of NeuN immunoreactive neurons inventral horn motor neurons of spinal cord in rats withnerve dissection showed that electroacupuncture can attenuate pain transduction and increase motor function. Also, NeuN was a good marker for identifying the degree of nerve cell loss after nervous system injury.

• 동의생리병리학회지
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• 제17권2호
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• pp.457-460
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• 2003

It has been suggested that oxidative stress of reactive oxygen species(ROS) may play an important role in the pathogenesis of neurological disorder. The aim of this study was to elucidate the oxidative stress of glucose oxidase(GO) in the cultured mouse spinal motor neurons and the preventing effect of Benincasae Semen(BS) on ROS-induced neurotoxicity. Cytotoxic effect of GO and protective effect of BS were performed by MTT assay. 30mU/ml GO decreased cell viability in dose-and time-dependent mannner, and BS diminished GO-induced neurotoxicity in these cultures. From above the results, ROS such as GO has toxic effect, and herb extract of BS is very effective against GO-induced neurotoxicity in cultured spinal motor neurons of neonatal mouse.