• The Korean Journal of Physiology and Pharmacology
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• 제28권5호
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• pp.413-422
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• 2024

Group I metabotropic glutamate receptors (mGluRs) modulate postsynaptic neuronal excitability and epileptogenesis. We investigated roles of group I mGluRs on low extracellular Mg²⁺ concentration ([Mg²⁺]_o)-induced epileptiform activity and neuronal cell death in the CA1 regions of isolated rat hippocampal slices without the entorhinal cortex using extracellular recording and propidium iodide staining. Exposure to Mg²⁺-free artificial cerebrospinal fluid can induce interictal epileptiform activity in the CA1 regions of rat hippocampal slices. MPEP, a mGluR 5 antagonist, significantly inhibited the spike firing of the low [Mg²⁺]_o-induced epileptiform activity, whereas LY367385, a mGluR1 antagonist, did not. DHPG, a group 1 mGluR agonist, significantly increased the spike firing of the epileptiform activity. U73122, a PLC inhibitor, inhibited the spike firing. Thapsigargin, an ER Ca²⁺-ATPase antagonist, significantly inhibited the spike firing and amplitude of the epileptiform activity. Both the IP₃ receptor antagonist 2-APB and the ryanodine receptor antagonist dantrolene significantly inhibited the spike firing. The PKC inhibitors such as chelerythrine and GF109203X, significantly increased the spike firing. Flufenamic acid, a relatively specific TRPC 1, 4, 5 channel antagonist, significantly inhibited the spike firing, whereas SKF96365, a relatively non-specific TRPC channel antagonist, did not. MPEP significantly decreased low [Mg²⁺]_o DMEM-induced neuronal cell death in the CA1 regions, but LY367385 did not. We suggest that mGluR 5 is involved in low [Mg²⁺]_o-induced interictal epileptiform activity in the CA1 regions of rat hippocampal slices through PLC, release of Ca²⁺ from intracellular stores and PKC and TRPC channels, which could be involved in neuronal cell death.

• Genes and Genomics
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• 제40권12호
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• pp.1331-1338
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• 2018

Although there have been plenty of dominance deviation analysis, few studies have dealt with multiple phenotypes. Because researchers focused on multiple phenotypes (final weight and backfat thickness) of Landrace pigs, the classification of the genes was possible. With genome-wide association studies (GWASs), we analyzed the additive and dominance effects of the single nucleotide polymorphisms (SNPs). The classification of the pig genes into four categories (overdominance in final weight, overdominance in backfat thickness and overdominance in final weight, underdominance in backfat thickness, etc.) can enable us not only to analyze each phenotype's dominant effects, but also to illustrate the gene ontology (GO) analysis with different aspects. We aimed to determine the additive and dominant effect in backfat thickness and final weight and performed GO analysis. Using additive model and dominance deviation analysis in GWASs, Landrace pigs' overdominant and underdominant SNP effects in final weight and backfat thickness were surveyed. Then through GO analysis, we investigated the genes that were classified in the GWASs. The major GO terms of the underdominant effects in final weight and overdominant effects in backfat thickness were ion transport with the SLC8A3, KCNJ16, P2RX7 and TRPC3 genes. Interestingly, the major GO terms in the underdominant effects in the final weight and the underdominant effects in the backfat thickness were the regulation of ion transport with the STAC, GCK, TRPC6, UBASH3B, CAMK2D, CACNG4 and SCN4B genes. These results demonstrate that ion transport and ion transport regulation genes have distinct dominant effects. Through GWASs using the mode of linear additive model and dominance deviation, overdominant effects and underdominant effects in backfat thickness was contrary to each other in GO terms (ion transport and ion transport regulation, respectively). Additionally, because ion transport and ion transport regulation genes are associative with adipose tissue accumulation, we could infer that these two groups of genes had to do with unique fat accumulation mechanisms in Landrace pigs.

• The Korean Journal of Physiology and Pharmacology
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• 제26권6호
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• pp.531-540
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• 2022

Group 1 metabotropic glutamate receptors (mGluRs) can positively affect postsynaptic neuronal excitability and epileptogenesis. The objective of the present study was to determine whether group 1 mGluRs might be involved in synaptically-induced intracellular free Ca²⁺ concentration ([Ca²⁺]_i) spikes and neuronal cell death induced by 0.1 mM Mg²⁺ and 10 µM glycine in cultured rat hippocampal neurons from embryonic day 17 fetal Sprague-Dawley rats using imaging methods for Ca²⁺ and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays for cell survival. Reduction of extracellular Mg²⁺ concentration ([Mg²⁺]_o) to 0.1 mM induced repetitive [Ca²⁺]_i spikes within 30 sec at day 11.5. The mGluR5 antagonist 6-Methyl2-(phenylethynyl) pyridine (MPEP) almost completely inhibited the [Ca²⁺]_i spikes, but the mGluR1 antagonist LY367385 did not. The group 1 mGluRs agonist, 3,5-dihydroxyphenylglycine (DHPG), significantly increased the [Ca²⁺]_i spikes. The phospholipase C inhibitor U73122 significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The IP₃ receptor antagonist 2-aminoethoxydiphenyl borate or the ryanodine receptor antagonist 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate also significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The TRPC channel inhibitors SKF96365 and flufenamic acid significantly inhibited the [Ca²⁺]_i spikes in the absence or presence of DHPG. The mGluR5 antagonist MPEP significantly increased the neuronal cell survival, but mGluR1 antagonist LY367385 did not. These results suggest a possibility that mGluR5 is involved in synaptically-induced [Ca²⁺]_i spikes and neuronal cell death in cultured rat hippocampal neurons by releasing Ca²⁺ from IP₃ and ryanodine-sensitive intracellular stores and activating TRPC channels.

• The Korean Journal of Physiology and Pharmacology
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• 제6권2호
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• pp.93-99
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• 2002

Effects of oxidized low-density lipoprotein (ox-LDL), $1-{\alpha}-stearoyl-lysophosphatidylcholine$ (LPC), on intracellular $Ca^{2+}$ concentration were examined in mouse endothelial cells by measuring intracellular $Ca^{2+}$ concentration $([Ca^{2+}]_i)$ with fura 2-AM and reverse transcription-polymerase chain reaction (RT-PCR). LPC increased $[Ca^{2+}]_i$ under the condition of 1.5 mM $[Ca^{2+}]_o$ but did not show any effect under the nominally $Ca^{2+}-free$ condition. Even after the store depletion with $30{\mu}M$ 2,5-di-tert- butylhydroquinone (BHQ) or $30{\mu}M$ ATP, LPC could still increase the $[Ca^{2+}]_i$ under the condition of 1.5 mM $[Ca^{2+}]_o.$ The time required to increase [$Ca{2+}$]i (about 1 minute) was longer than that for ATP-induced $[Ca^{2+}]_i$ increase $(10{\sim}30\;seconds).$ LPC-induced $[Ca^{2+}]_i$ increase was completely blocked by $1{\mu}M\;La^{3+}.$ Transient receptor potential channel(trpc) 4 mRNA was detected with RT-PCR. From these results, we suggest that LPC increased $[Ca^{2+}]_i$ via the increase of $Ca^{2+}$ influx through the $Ca^{2+}$ routes which exist in the plasma membrane.

• The Journal of Korean Physical Therapy
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• 제19권4호
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• pp.1-14
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• 2007

Background: It is generally accepted that skeletal muscle contraction is triggered by nerve impulse and intracellular $Ca^{2+}\;([Ca^{2+}]_i)$ released from intracellular $Ca^{2+}$ stores such as sarcoplasmic reticulum (SR). Specifically, this process, called excitation-contraction (E-C) coupling, takes place at intracellular junctions between the plasma membrane, the transverse (T) tubule L-type $Ca^{2+}$ channel (dihydropyridine-sensitive L-rype $Ca^{2+}$ channel, DHPR, also called tetrads), and the SR $Ca^{2+}$ release channel (ryanodine-sensitive $Ca^{2+}$ release channel, RyR, also called feet) of internal $Ca^{2+}$ stores in skeletal muscle cells. Furthermore, it has been reported that the $Ca^{2+-}$ dependent and -independent contraction determine the expression of skeletal muscle genes, thus providing a mechanism for tightly coupling the extent of muscle contraction to regulation of muscle plasticity-related excitation-transcription (E-T) coupling. Purpose: Expression and activity of plasticity-associated enzymes in gastrocnemius muscle strips have not been well studied, however. Methods: Therefore, in this study the expression and phosphorylation of E-C and E-T coupling-related mediators such as protein kinases, ROS(reactive oxygen species)- and apoptosis-related substances, and others in gastrocnemius muscles from rats was examined. Results: I found that expression and activity of MAPKs (mitogen-activated protein kinases, ERK1/2, p38MAPK, and SAPK/JNK), apoptotic proteins (cleaved caspase-3, cytochrome c, Ref-1, Bad), small GTP-binding proteins (RhoA and Cdc42), actin-binding protein (cofilin), PKC (protein kinase C) and $Ca^{2+}$ channel (transient receptor potential channel 6, TRPC6) was observed in rat gastrocnemius muscle strips. Conclusion: These results suggest that MAPKs, ROS- and apoptosis-related enzymes, cytoskeleton-regulated proteins, and $Ca^{2+}$ channel may in part functionally import in E-C and E-T coupling from rat skeletal muscles.

• Clinical and Experimental Pediatrics
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• 제52권11호
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• pp.1260-1266
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• 2009

목 적 : 특발성 신증후군은 소아의 가장 흔한 일차성 사구체 질환 중의 하나이다. 신증후군은 초기 경구 스테로이드 치료에 대한 반응에 따라서 임상적으로 스테로이드 반응성 신증후군과 스테로이드 저항성 신증후군으로 분류될 수 있다. 그러나 현재까지 신증후군에서 스테로이드의 정확한 작용 기전은 알려져 있지 않다. 신증후군 환자를 대상으로 여러 가지 유전자 다형성을 분석함으로써 스테로이드 치료에 대한 반응의 차이를 설명하려는 여러 시도들이 있어왔다. 방 법 : 본 연구에서는 190명의 신증후군 환자를 대상으로 NR3C1 유전자 다형성(ER22/23EK, N363S, BclI)을 확인하여 유전형과 임상-병리 양상의 연관성에 대해서 분석하였다. 결 과 : 신증후군 환자의 평균 연령은 4.95세였고 남아가 134명이었다. 11명의 환자는 신증후군의 가족력이 있었다. 그러나 이 환자들을 대상으로 NPHS2, WT1, ACTN4, TRPC6 유전자 분석을 시행한 결과 이상 소견은 발견되지 않았다. 80명의 환자(42.1%)는 초기 스테로이드 저항성이었고 그 중 31명의 환자는 말기 신질환으로 진행하였다. 신장 조직 검사는 113명의 환자를 대상으로 시행되었고 그 중 36명의 환자(31.9%)는 미세변화 신증후군이었고 77명의 환자(68.1%)는 초점성 분절성 사구체 경화증이었다. BclI 유전형을 비교하였을 때 G allele 빈도는 환자군과 대조군에서 차이가 없었다. ER22/23EK과 N363S 유전형은 각각 ER/ER과 NN으로 환자군과 대조군에서 동일한 양상을 보였다. BclI 유전형은 신증후군의 발병 나이, 초기 스테로이드 반응 여부, 신장의 병리학적 소견, 말기 신질환으로의 진행여부와 연관성을 보이지 않았다. 결 론 : 한국 신증후군 환아를 대상으로 한 이 연구 결과는 NR3C1 유전자의 ER22/23EK, N363S 및 BclI 유전자 다형성이 신증후군의 발병, 초기 스테로이드 치료에 대한 반응, 신장의 조직학적 소견 및 신 기능의 저하에 영향을 미치지 않음을 보여준다.