• The Korean Journal of Physiology and Pharmacology
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• 제28권2호
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• pp.165-181
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• 2024

The slow and regular pacemaking activity of midbrain dopamine (DA) neurons requires proper spatial organization of the excitable elements between the soma and dendritic compartments, but the somatodendritic organization is not clear. Here, we show that the dynamic interaction between the soma and multiple proximal dendritic compartments (PDCs) generates the slow pacemaking activity in DA neurons. In multipolar DA neurons, spontaneous action potentials (sAPs) consistently originate from the axon-bearing dendrite. However, when the axon initial segment was disabled, sAPs emerge randomly from various primary PDCs, indicating that multiple PDCs drive pacemaking. Ca²⁺ measurements and local stimulation/perturbation experiments suggest that the soma serves as a stably-oscillating inertial compartment, while multiple PDCs exhibit stochastic fluctuations and high excitability. Despite the stochastic and excitable nature of PDCs, their activities are balanced by the large centrally-connected inertial soma, resulting in the slow synchronized pacemaking rhythm. Furthermore, our electrophysiological experiments indicate that the soma and PDCs, with distinct characteristics, play different roles in glutamate-induced burst-pause firing patterns. Excitable PDCs mediate excitatory burst responses to glutamate, while the large inertial soma determines inhibitory pause responses to glutamate. Therefore, we could conclude that this somatodendritic organization serves as a common foundation for both pacemaker activity and evoked firing patterns in midbrain DA neurons.

• 생명과학회지
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• 제15권4호
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• pp.600-606
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• 2005

신경미세섬유(neurofilament, NF) 단백질은 신경세포의 주된 중간세사로서, NF-L (61 kDa), NF-M (90 kDa) 및 NF-H (115 kDa) 단백질의 공동중합체로 구성된다. 신경세사섬유는 신경세포의 성장, 구성, 형태 및 가소성에 중요한 역할을 하지만 발생학적 표현에 대하여는 아직 잘 알려지지 않았다. 본 연구에서는 NF-M에 특이한 항체를 제조하여 배양한 대뇌신경세포에서 NF-M의 표현을 조사하였다. 배양 12 및 24시간 세포에서 NF-M은 축삭과 그 성장추 그리고 축삭에 가까운 세포체에 강하게 표현하였다. 배양 4 및 14일 신경세포를 NF-M과 PSD95 항체로 이중염색한 결과 NF-M은 축삭과 가지돌기에 공히 강하게 표현되었으며, PSD95와 같이 위치할 경우에는 점박이로 나타났다. .면역염색에서도 NF-M이 PSD 분획에서 검출되었는데, 따라서 이 점박이는 가지돌기가시임을 시사한다. 본 연구의 결과는 NF-M이 신경세포의 초기 형태발달과정에서 축삭으로 강하게 몰려가며, 성숙한 신경세포에서는 가지돌기 및 가지돌기가시에도 위치하여 특정기능을 수행함을 시사한다.

• Applied Microscopy
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• 제28권2호
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• pp.139-158
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• 1998

The development of the superior cervical ganglion was studied by electron microscopic method in human fetuses ranging from 40 mm to 260 mm of crown-rump length (10 to 30 weeks of gestational age). At 40 mm fetus, the superior cervical ganglion was composed of clusters of undifferentiated cell, primitive neuroblast, primitive supporting cell, and unmyelinated fibers. At 70mm fetus, the neuroblasts and their processes were ensheated by the bodies or processes of satellite cells. The cytoplasm of the neuroblast contained rough endoplasmic reticulum, mitochondria, Golgi complex, Nissl bodies and dense-cored vesicles. As the neuroblasts grew and differentiated dense-cored vesicles moved away from perikaryal cytoplasm into developing processes. Synaptic contacts between the cholinergic axon and dendrites of postganglionic neuron and a few axosomatic synapses were first observed at 70 mm fetus. At 90 mm fetus the superior cervical ganglion consisted of neuroblasts, satellite cells, granule-containing cells, and unmyelinated nerve fibers. The ganglion cells increased somewhat in numbers and size by 150 mm fetus. Further differentiation resulted in the formation of young ganglion cells, whose cytoplasm was densely filled with cell organelles. During next prenatal stage up to 260 mm fetus, the cytoplasm of the ganglion cells contained except for large pigment granules, all intracytoplasmic structures which were also found in mature superior cervical ganglion. A great number of synaptic contact zones between the cholinergic preganglionic axon and the dendrites of the postganglionic neuron were observed and a few axosomatic synapses were also observed. Two morphological types of the granule-containing cells in the superior cervical ganglion were first identified at 90 mm fetus. Type I granule-containing cell occurred in solitary, whereas type II tended to appeared in clusters near the blood capillaries. Synaptic contacts were first found on the solitary granule-containing cell at 150 mm fetus. Synaptic contacts between the soma of type I granule-containing cells and preganglionic axon termials were observed. In addition, synaptic junctions between the processes of the granule- containing cells and dendrites of postganglionic neuron were also observed from 150 mm fetus onward. In conclusion, superior cervical ganglion cells and granule-containing cells arise from a common undifferentiated cell precursor of neural crest . The granule-containg cells exhibit a local modulatory feedback system in the superior cervical ganglion and nay serve as interneurons between the preganglionic and postganglionic cells.

• Medical Lasers
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• 제10권4호
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• pp.195-200
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• 2021

Evidence shows that nerve injury triggers mitochondrial dysfunction during axonal degeneration. Mitochondria play a pivotal role in axonal regeneration. Therefore, normalizing mitochondrial energy metabolism may represent an elective therapeutic strategy contributing to nerve recovery after damage. Photobiomodulation (PBM) induces a photobiological effect by stimulating mitochondrial activity. An increasing body of evidence demonstrates that PBM improves ATP generation and modulates many of the secondary mediators [reactive oxygen species (ROS), nitric oxide (NO), cyclic adenosine monophosphate (cAMP), and calcium ions (Ca²⁺)], which in turn activate multiple pathways involved in axonal regeneration.

• 동의생리병리학회지
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• 제21권1호
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• pp.145-152
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• 2007

Following CNS injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, gliosis. Astrocyte-rich gliosis relates with up-regulation of GFAP and CD81, and eventually becomes physical and mechanical barrier to axonal regeneration. It is postulated that the astrocytic reaction is absent, regeneration of axons can occur. And it was reported that treatment with anti CD81 antibodies enhanced functional recovery in the rat with spinal cord injury. So in this current study, the author investigated the effect of the water extract of Persicae Semen on the regulation of GFAP and CD81 that increase when gliosis occurs. Persicae Semen decreased the expression of GFAP and CD81 in astrocyte cell by ELISA method. Persicae Semen decreased the RNA expression of CD81 and GFAP. The proteins that separate in whole cell were analaysed by western blot, and the expression of GFAP and CD81 was decreased. In vivo, rats brains were peformed cortical stab wound, the water extracts of Persicae Semen were injected for 7 days, 30 days. As a result, GFAP and CD81 expression were decreased in immunohistochemistry. These findings demonstrate that Persicae Semen decreases GFAP and CD81 expression. Accordingly, Persicae Semen could be a candidate for promotion of axon regeneration after CNS injury.

• Applied Microscopy
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• 제18권2호
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• pp.177-186
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• 1988

Degeneration of the axon terminals of mamillo-thalamic tract following the electrical coagulation of mamillary body is well known. In this study, the author investigated the ultrastructural alterations of neuropil components, initiated by terminal degenerations. Rats weighing approximately 250 gm were fixed on the stereotaxic instrument(David Kopf Inc., Heavy duty model), and NE 300 active electrode(Rhodes Med. Instr. Inc.) was introduced to the mamillary position of anterior 3.8 mm, lateral 0.5 mm, height 3.8 mm and lateral angle of $23^{\circ}$ according to De Groot's Atlas. Electric current of 20 mA was applied during 1 minute between active and inactive electrodes with Radio Frequency Lesion Generator(RFG 4, Radionics Inc.). Two hours, 2 days, 1 week and 2 weeks following the electrical coagulation of mamillary body, ipsilateral anterior thalamic nucleus was fixed in 1% glutaraldehyde-l% paraformaldehyde and 2% osmium tetroxide, embedded in Araldite mixture, cutted with LKB ultra tome V, stained with uranyl acetate-lead citrate and observed with JEOL 100 CX electron microscope. Observed results were as follows; 1. Degenerated mamillo-thalamic synapses were observed to form asymmetric axospinous or axo-dendritic types. 2. Terminal degeneration was not easily discernible at 2 hours interval after mamillary lesion, but following 2 days the terminal degeneration was apparent. 3. Postsynaptic spines, dendrites and even their cell bodies show edematic changes caused by the degeneration of postsynaptic counterpart. 4. Astrocytic territories, including perivascular processes forming glial limitans of blood-brain barrier, exhibit remarkable expansion. 5. Oligoglia and astroglia are actively engaged in the removal of degenerated elements. 6. Active forms of microglia were increased. 7. The observed results may represent typical ultrastructural alteration pattern within neuropil following the degeneration of certain input axon terminals.

• The Journal of Korean Physical Therapy
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• 제13권2호
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• pp.281-292
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• 2001

This study was performed to investigate the effect of therapeutic exercise on brain-derived neurotrophic factor manifestation after global brain ischemia in rats. Nine rats with global ischemia were divided at random into two group. In the control group, three rats remained in cage. But, in the end, two rats were alive. In the therapeutic exercise group, six rats remained. The five rats of this group was swam for 30 minutes everyday for a week. The brain-derived neurotrophic factor expression was identified from immunohistochemistry. The results of this study were as follows : 1. In the control group, a little expression of brain-derived neurotrophic factor was observed at cortex and hippocampus layer, but cell body and axon was observed obscurely. 2. In the experimental group, a much expression of brain-derived neurotrophic factor was observed at cortex and hippocampus layer, and cell body and axon was observed clearly. In the neurological examination(beam-walking test). experimental group was obtained higher 1.4 points than control group. BDNF expression was increased by swimming for 30 minutes everyday for a week. Therefore, therapeutic exercise contribute to brain plasticity after brain ischemia.

• Applied Microscopy
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• 제23권1호
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• pp.15-24
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• 1993

버들붕어 뇌와 아가미의 미세구조에 미치는 메틸수은의 독성적 영향과 이에 대한 홍삼의 보상효능을 전자현미경적 방법에 의하여 연구하였다. 뇌 신경세포의 미세구조 변화에 있어서 대조군에 비하여 메틸수은만을 투여한 군에서는 수상돌기와 축색돌기가 상당히 확장되고 핵질과 세포질이 부분적으로 손실되었으며 ribosome의 수적감소와 mitochondria의 팽대가 관찰되었다. 그리고 파괴된 핵과 공포화된 mitochondria를 함유한 괴사세포의 출현은 특이한 관찰이었다. 반면 메틸수은과 홍삼을 병행 투여한 군에서는 메틸수은만을 투여한 군에서 보다 수상돌기와 축색돌기의 확장이 감소되고 ribosome의 수가 증가되었으며 mitochondria의 팽대정도가 상당히 감소되었다. 아가미 새판의 미세구조에 있어서는 Pillar cell과 arm의 붕괴, 표피세포의 확장 및 기저막의 비후가 메틸수은만을 투여한 군에서 관찰되었고 메틸수은과 홍삼을 병행 투여한 군에서는 메틸수은만을 투여한 군에서 보다 arm의 붕괴정도와 기저막의 비후정도가 감소되어 정상세포와 거의 같은 정도로 호전되었다.

• The Korean Journal of Pain
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• 제29권1호
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• pp.3-11
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• 2016

A nerve block is an effective tool for diagnostic and therapeutic methods. If a diagnostic nerve block is successful for pain relief and the subsequent therapeutic nerve block is effective for only a limited duration, the next step that should be considered is a nerve ablation or modulation. The nerve ablation causes iatrogenic neural degeneration aiming only for sensory or sympathetic denervation without motor deficits. Nerve ablation produces the interruption of axonal continuity, degeneration of nerve fibers distal to the lesion (Wallerian degeneration), and the eventual death of axotomized neurons. The nerve ablation methods currently available for resection/removal of innervation are performed by either chemical or thermal ablation. Meanwhile, the nerve modulation method for interruption of innervation is performed using an electromagnetic field of pulsed radiofrequency. According to Sunderland's classification, it is first and foremost suggested that current neural ablations produce third degree peripheral nerve injury (PNI) to the myelin, axon, and endoneurium without any disruption of the fascicular arrangement, perineurium, and epineurium. The merit of Sunderland's third degree PNI is to produce a reversible injury. However, its shortcoming is the recurrence of pain and the necessity of repeated ablative procedures. The molecular mechanisms related to axonal regeneration after injury include cross-talk between axons and glial cells, neurotrophic factors, extracellular matrix molecules, and their receptors. It is essential to establish a safe, long-standing denervation method without any complications in future practices based on the mechanisms of nerve degeneration as well as following regeneration.

• Journal of Acupuncture Research
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• 제24권6호
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• pp.137-148
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• 2007

Objectives : Following central nervous system (CNS) injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, know as gliosis. As well,myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates to up-regulation of GFAP and CD81, and eventually becomes a physical and mechanical barrier to axonal regeneration. It is postulated that when the astrocytic reaction is absent, regeneration of axons can occur. It was reported that treatment with anti CD81 antibodies enhanced functional recovery in rats with spinal cord injury. Methods : MAG is one of several endogenous axon regeneration inhibitors that limit recovery from central nervous system injury and disease. It was reported that molecules which block such inhibitors enhanced axon regeneration and functional recovery. Results : In this current study, the author investigated the effect of the water extract of Ginseng Radix on the regulation of CD81, GFAP and MAG which increases when gliosis occurs. MTT analysis was performed to examine cell viability, and cell based ELISA, Western Blot and PCR were used to detect the expression of CD81, GFAP and MAG. Immunohistochemistry was also performed to confirm in vivo. Conclusions : We observed that Ginseng Radix significantly down-regulates the expression of CD81, GFAP and MAG by means of cell based ELISA, Western Blot and PCR. In immunohistochemistry, expression of CD81, GFAP and MAG also decreased. Taken together, these results suggest that Ginseng Radix can be a candidate for regenerating CNS injury.