• Progress in Medical Physics
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• v.9 no.2
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• pp.95-104
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• 1998

The dynamic properties of the 3rd-order neuron of the retina was investigated by using conventional intracellular recording techniques. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus. The cornea, iris, lens, and vitreous were removed by absorption with Kimwipe tissue under the dissection microscope thereby exposing the retina in a hemi -eyecup. The electrical signal was amplified by electrometer, viewed on oscilloscope. Regular signals from the cells were recorded on a penwriter and stored by data recorder and computer. Full-field, spot or annular light stimuli were generated on a computer monitor and focused onto the retina. Baclofen hyperpolarized the dark membrane potential, suppressed sustained component and enhanced transient component of the ON-sustained cell with a large transient component, but did not affect the surround antagonism of the cell. Baclofen selectively suppressed responses evoked by moving bar light stimuli on the ON-OFF transient cell. The results suggest that transient cells have directional selectivity in the inner retina. These dynamic properties of amacrine and ganglion cells were modulated by baclofen. Therefore, it is presumed that there is baclofen-induced directional selectivity in ON-OFF transient cells in the catfish retina.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.225-239
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• 1987

The effects of adenosine on the mechanical contractions and electrical activities were investigated in guinea-pig stomach. Spontaneous contractions of the antral region were recorded with force transducer, and the phasic contractions of fundic region were induced by electrical field stimulation. Electrical responses of smocth muscle cells were recored using glass capillary microelectrodes filled with 3M-KCl. Field stimulation was applied transmurally by using a pair of platinum wire (0.5 mm in diameter) placed on both sides of tissue. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows. 1) Adenosine suppressed the spontaneous contractions of antrum in a dose-dependent manner. 2) The inhibitory effect on antral spontaneous contractions was not influenced by the administration of guanethidine $(5{\times}10^{-6}\;M)$ and atropine $10^{-6}\;M$, or in the presence of dipyridamole $10^{-7}\;M$. 3) The phasic contractions of fundus induced by electrical field stimulation, which disappeared rapidly by the addition of tetrodotoxin $(3{\times}10^{-7}\;M)$, were potentiated by adenosine in the presence of guanethidine. 4) Adenosine decreased the amplitude and the maximum rate of rise of slow waves, and the increased amplitude and rate of rise evoked in the high calcium solution or in the presence of TEA were decreased by adenosine. 5) The non-adrenergic, non-cholinergic inhibitory junction potential (IJP) was inhibited by adenosine in the antral region, while the excitatory junction potential (EJP) in the fundic region was potentiated. From the above results, the following conclusions could be made. 1) Adenosine suppresses the spontaneous contractions of antrum strip by the decrease in amplitude and rate of rise of slow waves. 2) The release of neurotransmitter(s) from non-adrenergic, non-cholinergic nerve terminals is inhibited by adenosine.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.6
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• pp.356-362
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• 2019

Scutellaria baicalensis (SB) has widely used in the treatment for various brain diseases in the field of Oriental medicine. Biofermantation of SB can make major chemical constituents of SB to pass blood-brain barrier easily and to have more potent anti-oxidant ability. There is a little information about the contribution of fermented SB (FSB) to the formation or maintenance of the neural plasticity in the hippocampus. The purpose of this study was to evaluate effects of FSB extract on hydrogen peroxide (H₂O₂) - induced impairments of the induction and maintenance of long-term potentiation (LTP), an electrophysiological marker for the neural plasticity in the hippocampus. From hippocampal slices of rats, the field excitatory postsynaptic potentials (fEPSPs) were evoked by the electrical stimulation to the Schaffer collaterals - commissural fibers in the CA1 areas and LTP by theta-burst stimulation by using 64 - channels in vitro multi-extracellular recording system. In order to induce oxidative stress to hippocampal slices two different concentrations (200, 400 μM) of H₂O₂ were given to the perfused aCSF before and after the LTP induction, respectively. The ethanol extract of FBS with concentration of 25 ㎍/ml, 50 ㎍/ml was diluted in perfused aCSF that had 200 μM H₂O₂, respectively. Oxidative stress by the treatment of H₂O₂ resulted in decrease of the induction rate of LTP in the CA1 area with a dose - dependent manner. However, the ethanol extract of FSB prevented the reduction of the induction rate of LTP caused by H₂O₂ - induced oxidative stress with a dose - dependent manner. These results may support a potential application of FSB to ameliorate impairments of hippocampal dependent neural plasticity or memory caused by oxidative stress.

• Archives of Craniofacial Surgery
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• v.11 no.1
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• pp.28-32
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• 2010

Purpose: In accordance with the increasing number of accidents caused by various reasons and recently developed fine diagnostic skills, the incidence of orbital blow-out fracture cases is increasing. As it causes complications, such as diplopia and enophthalmos, surgical reduction is commonly required. This article reports a retrospective series of 5 blow-out fracture cases that had unusual nerve injuries after reduction operations. We represents the clinical experiences about treatment process and follow-up. Methods: From January 2000 to August 2009, we treated total 705 blow-out fracture patients. Among them, there were 5 patients (0.71%) who suffered from postoperative neurologic complications. In all patients, the surgery was performed with open reduction with insertion of $Medpor^{(R)}$. Clinical symptoms and signs were a little different from each other. Results: In case 1, the diagnosis was oculomotor nerve palsy. The diagnosis of the case 2 was superior orbital fissure syndrome, case 3 was abducens nerve palsy, and case 4 was idiopathic supraorbital nerve injury. The last case 5 was diagnosed as optic neuropathy. Most of the causes were extended fracture, especially accompanied with medial and inferomedial orbital blow-out fracture. Extensive dissection and eyeball swelling, and over-retraction by assistants were also one of the causes. Immediately, we performed reexploration procedure to remove hematomas, decompress and check the incarceration. After that, we checked VEP (visual evoked potential), visual field test, electromyogram. With ophthalmologic test and followup CT, we can rule out the orbital apex syndrome. We gave $Salon^{(R)}$ (methylprednisolone, Hanlim pharmaceuticals) 500 mg twice a day for 3 days and let them bed rest. After that, we were tapering the high dose steroid with $Methylon^{(R)}$ (methylprednisolon 4 mg, Kunwha pharmaceuticals) 20 mg three times a day. Usually, it takes 1.2 months to recover from the nerve injury. Conclusion: According to the extent of nerve injury after the surgery of orbital blow-out fracture, the clinical symptoms were different. The most important point is to decide quickly whether the optic nerve injury occurred or not. Therefore, it is necess is to diagnose the nerve injury immediately, perform reexploration for decompression and use corticosteroid adequately. In other words, the early diagnosis and treatment is most important.