• Clinical and Experimental Pediatrics
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• 제52권5호
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• pp.588-593
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• 2009

목 적 : 산소-포도당 박탈(oxygen-glucose deprivation, OGD)에 노출된 신생 흰쥐 해마 절편에서 성장호르몬이 신경 세포 보호 효과가 있는지를 연구하고자 하였다. 방 법 : 배양된 생후 7일된 신생 흰쥐의 해마 절편을 OGD에 60분간 노출 시켰다. 이후 각기 다른 세 용량의 성장 호르몬(5, 50, $500{\mu}M$)을 배양액에 투여하고 OGD 노출 후 12 와 24시간에 해마 절편의 상대적 propidium iodide (PI) uptake와 배양액의 상대적 lactate dehydrogenase (LDH) 활성도를 측정하여 성장 호르몬 처치군과 성장 호르몬 처치하지 않은 대조군 사이에 비교하였다. 신경 세포의 세포 사멸에 대한 성장호르몬의 효과를 관찰하고자 caspase-3의 면역 형광 염색과 TUNEL 염색을 시행하였다. 결 과 : 1) 각기 다른 세 용량의 성장호르몬을 처치한 해마 절편의 CA1과 DG에서 상대적 PI uptake는 처치하지 않은 대조군에 비해 OGD 노출 후 12시간과 24시간에 의미 있는 차이를 보이지 않았다(P>0.05). 2) 상대적 LDH 활성도는 OGD 노출 후 12시간에만 성장 호르몬을 투여한 군의 배양액에서 대조군에 비해 통계적으로 의미 있게 감소하였다(P<0.05). 3) 성장 호르몬($50{\mu}M$)으로 처치한 해마 절편의 CA1과 DG에서 caspase-3 발현과 TUNEL 양성의 발현은 OGD 노출 후 12와 24시간에 대조군과 차이를 보이지 않았다. 결 론 : OGD에 노출된 해마 절편에서 성장호르몬 처치는 확실한 신경세포 보호 효과를 보이지 않았으나 OGD 노출 후 12시간에 배양액으로 LDH 유출을 감소시킬 수 있었다.

• 한국발생생물학회지:발생과생식
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• 제4권1호
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• pp.95-100
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• 2000

환경에 방출되어 있는 많은 내분비교란물질들은 사람과 동물의 내분비계에 교란을 일으킬 수 있는 잠재력을 가진다. 뇌의 성분화는 생식소 호르몬 영향하에 비가역적으로 진행되며 흰쥐의 경우 이 시기는 임신말기에서 생후 7∼10일 가량이다. 최근에 본 연구진은 횐쥐의 뇌 성 분화의 결정적인 시기에 발현되는 KAP3유전자를 클로닝하였다 (Choi ＆ Lee, 1999). KAP3의 기능은 신경세포를 포함한 세포에서 aronal tansport를 조절하는 것으로 알려져 있다. 본 연구에서는 흰쥐 뇌 발생의 결정적인 시기에 내분비 교란물질인 Dichlorodiphenyl trichloroethane (DDT)가 KAP3유전자 발현과 성분화에 미치는 영향을 검토하였다. DDT에 노출된 임신 17일된 흰쥐 태아 암컷과 수컷의 뇌에서 KAP3 mRNA의 발현이 증가하였다. 그러나 출생후 DDT에 노출된 흰쥐 암컷과 수컷의 뇌에서는 KAP3 mRNA의 발현은 감소하였다. 또한 태어난 직후 DDT에 노출된 경우 체중이 현저히 감소하였으며 수정율도 DDT에 노출되지 않은 흰쥐에 비하여 크게 낮았다. 이러한 결과는 내분비 교란물질인 DDT가 뇌의 성 분화와 관련된 유전자인 KAP3의 전사에 영향을 미치며, 내분비 교란물질에 노출된 태아의 뇌 분화에서 독성을 보이는 것을 의미한다. 그리고 KAP3유전자는 동물의 신경세포의 발생에 미치는 내분비 교란 물질의 독성을 분자생물학적으로 연구하기 위한 유전자 지표로도 사용 가능하다고 생각된다.

• International Journal of Oral Biology
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• 제34권4호
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• pp.215-222
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• 2009

Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)-$\alpha$-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the $IP_3$ receptor antagonist 2-APB, and following the depletion of the intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular $Ca^{2+}$ store via the PLC-$IP_3$ pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.237-245
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• 2016

Direct communication between neighboring cells via gap junction in tissue is important for maintenance and regulation of its physiological functions. Each epididymal region has different composition of cell types. It is well recognized that the epididymis is a steroid hormone-responsive tissue. The present study was designed to determine the effect of estradiol benzoate (EB) or flutamide exposured at the early postnatal age on the expression of connexin (Cx) isoforms in the caudal epididymis. The EB or flutamide was subcutaneously administrated to male Spragure Dawley rat at 7 days of age, and expressional changes of Cx isoforms in the adult corpus epididymis were determined by quantitative real-time PCR. The treatment of low-dose EB resulted in decreases of Cx30.3, Cx31.1, Cx37, and Cx45 expression but caused an increase of Cx32 expression. Exposure to high-dose EB led into expressional increases of Cx31, Cx31.1, Cx32, Cx40, and Cx43, even though a decrease of Cx37 expression was found with a high-dose EB treatment. A low-dose flutamide induced increases of Cx31, Cx31.1, Cx32, and Cx43 expression but a decrease of Cx37 expression. Expression of most Cx genes were significantly increased by a high-dose flutamide, while no expressional change of Cx26 and Cx40 was detected by a high-dose flutamide. These results indicate that expression of Cx isoforms in the caudal epididymis is altered by exposure to steroidal compounds at the prepubertal age. It is suggested that a contact with environmental exogenous materials during the early postnatal period would lead to alteration of epididymal functions at the adult.

• 동의신경정신과학회지
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• 제12궈1호
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• pp.137-149
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• 2001

Cytokines are polypeptides which possess various biological properties affecting. host defense function and response to disease. Inflammatory cytokines, tumor necrosis $factor-{\alpha}$(TNF-${\alpha}$), interleukin(IL)-1 and IL-6 induce inflammation, fever, hypotension and pain when injected into animals or human subject. When glial cell cultures were prepared from neonatal mice or rats, astrocytes were reported to produce these inflammatory cytokines to viral infection, lipopolysaccharide(LPS), or cytokines. The purpose of this study was to investigate the regulatory effect of these cytokines secretion from primary cultures of rat astrocytes. Substance P(SP) can stimulate secretion of TNF-${\alpha}$ from astrocytes stimulated with LPS. Sesim-Tang significantly inhibited the TNF-${\alpha}$ secretion by astrocytes stimulated with SP and LPS. IL-1 has been shown to elevate TNF-${\alpha}$ secretion from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. We therefore also investigated whether IL-1 mediated inhibition of TNF-${\alpha}$ secretion from primary astrocytes by Sesim-Tang. Treatment of Sesim-Tang to astrocytes stimulated with both LPS and SP decreased IL-1 secretion significantly. The secretion of TNF-${\alpha}$ by LPS and SP in astrocytes was progressively inhibited with increasing amount of IL-1 neutralizing antibody. Furthermore Sesim-Tang inhibited the IL-6 secretion by astrocytes stimulated with SP and LPS. The inhibitory effect of inflammatory cytokines by Sesim-Tang, observed in this study, might reflect an antiinflammatory activity and a reduction of various-type pains, fever etc. in the central nervous system.

• 동의생리병리학회지
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• 제21권2호
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• pp.432-437
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• 2007

Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS are also involved in persistent pain through a spinal mechanism. In the present study, whole cell patch clamp recordings were carried out on substantia gelatinosa (SG) neurons in spinal cord slice of neonatal rats to investigate the effects of ROS on neuronal excitability and excitatory synaptic transmission. In current clamp condition, tert-buthyl hydroperoxide (t-BuOOH), an ROS donor, induced a electrical hyperexcitability during t-BuOOH wash-out followed by a brief inhibition of excitability in SG neurons. Application of t-BuOOH depolarized membrane potential of SG neurons and increased the neuronal firing frequencies evoked by depolarizing current pulses. Phenyl-N-tert-buthylnitrone (PBN), an ROS scavenger, antagonized t-BuOOH induced hyperexcitability. IN voltage clamp conditions, t-BuOOH increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). In order to determine the site of action of t-BuOOH, miniature excitatory postsynaptic currents (mEPSCs) were recorded. t-BuOOH increased the frequency and amplitude of mEPSCs, indicating that it may modulate the excitability of the SG neurons via pre- and postsynaptic actions. These data suggest that ROS generated by peripheral nerve injury can induce central sensitization in spinal cord.

• Toxicological Research
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• 제6권2호
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• pp.191-204
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• 1990

Trimethyltin (TMT) induced lesions in the rat hippocampal formation was reviewed. Adult rats were treated with a single dose of 6.0 mg TMT/kg b.w. and were sacrificed between 3-60 days following exposure. On the hippocampal formation, the granule cells of fascia dentata showed early changes which subsided considerably at a later time when the destruction of the pyramidal neurons of the Ammon's horn became increasingly pronounced with time, leading to severe destruction of the structure. It is interesting to note that there was an inverse relationship of pathological involvement between the f.d. granule cells and the Ammon's horn neurons; i.e., when there was a large sparing of the granule cells. there was an extensive damage to the Ammon's horn and vice versa. This inverse relationship was also true between the $CA_3$neurons and the $CA_{1,2}$neurons in the Ammon's horn. Progressive zinc loss, as demonstrated by Timm's method, on the Mossy fibers was also observed. Similar Mossy fiber zinc depletion has been demonstrated in electrical stimulatory excitation condition of the perforant path to the hippocampus. Depletion of corticosterone, an inhibitor to the hippocampal neurons, by means of adrenalectomy will exaggerate the TMT induced hippocampal lesion. Neonatal study revealed that a unique degenerative pattern of the Ammon's horn could be established in accordance with exposure to TMT at specific maturation periods of the fippocampal formation: increasing destruction of the Ammon's horn with increasing synaptogenesis between the f.d. granule cells and the Ammon's horn neurons. Thus it is apparent that the damage of the Ammon's horn, upon exposure to TMT, may depend on the integrity and functional state of the f.d. granule cells. A hyperexcitory scheme and mechanism as the toxicity basis of TMT in the hippocampal formation is proposed and discussed.

• Biomolecules & Therapeutics
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• 제20권1호
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• pp.75-80
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• 2012

The aim of this study was to explore the role and effect of ginsenosides Rg1 on osteoblasts cultured with Ti particles. Osteoblasts from neonatal rats were cultured with particles and different doses of Rg1, the main active ingredient in ginsenosides Rg1. We found that the COX-2, $PGE_2$, TNF-${\alpha}$, IL-1, and IL -6 concentrations in the medium of cells cultured with Ti particles significantly increased as compared with that of the control cells (p<0.05 or p<0.01). In addition, cells cultured with Ti particles alone exhibited the highest concentrations of these molecules. The $PGE_2$, TNF-${\alpha}$, IL-1, and IL-6 levels in the medium of cells cultured with Rg1 were in between those of the control cells and the cells cultured with Ti particles alone. The IL-1ra level in the group cultured with Ti and medium-dose Rg1 was the highest followed by the cells cultured with Ti and high-dose Rg1 and those cultured with Ti and low-dose Rg1 (p<0.05). In conclusion, ginsenosides can reduce the levels of infl ammatory cytokines produced by osteoblasts on induction with Ti particles and can prevent prosthesis loosening.

• The Korean Journal of Physiology and Pharmacology
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• 제11권3호
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• pp.113-119
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• 2007

Developmental disability shows life-long behavioral abnormality with no significant physical malformation. This study was undertaken to develop an animal model for developmental disability by using two-factor approach. Lipopolysaccharide (LPS), a bacterial toxin, and NAN-190, a $5-HT_{1A}$ receptor antagonist, were administered to Sprague-Dawley rats on postnatal day (PND) 5 to induce inflammation and an altered 5-HT system, respectively. Long-term alteration of behavior occurred in the drug-treated groups. The LPS-treated group showed impaired motor coordination in the Rota-rod test. The LPS- treated or both LPS and NAN-190-treated groups showed impaired fore-paw muscle power in the wire maneuver test. These groups also showed decreased white matter volume and increased serotonergic fibers. The LPS and NAN-190-treated group also exhibited neurologic deficit in the placing reaction test and impaired equilibrium function in the tilt table test. The results showed that a variety of altered behaviors can be generated by two factor model, and suggested that combination of important etiologic factors and possible underlying defects is a promising strategy of establishing an animal model for developmental disabilities.

• The Korean Journal of Physiology and Pharmacology
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• 제8권1호
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• pp.17-20
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• 2004

PTEN (phosphatase and tensin homolog) is a dual specific phosphatase antagonizing phosphoinositide 3-kinase activity, and has first been cloned as a tumor suppressor for glioma. Although the role of PTEN as a tumor suppressor has been well studied, little is known about signaling mechanisms regulating expression and/or activity of PTEN in the central nervous system. In this study, we investigated whether PTEN expression is regulated by sensory deprivation. P5 rat pups were unilaterally naris-closed, and olfactory bulbs were immunohistochemically analyzed with PTEN antibody at the $7^{th}$ day after naris closure. PTEN immunoreactivity was found to be down-regulated in both glomerular, external plexiform and subependymal cell layers, suggesting that odor deprivation signals down-regulate expression of PTEN in the olfactory bulb. To the best of our knowledge, this is the first report to suggest that PTEN expression is regulated by sensory deprivation signals in neonatal rats.