• Food Science and Preservation
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• v.31 no.2
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• pp.298-306
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• 2024

This study evaluated the differentiation and protective effects of mixed plant-extract powder in C2C12 muscle cells. Cells were differentiated into myotubes in 2% horse serum (HS)-containing medium with mixed plant-extract powder (MPEP) for 6 days. Treatment with MPEP increased the expression of myogenin and myosin heavy chain (MHC) protein in cells compared with non-treated cells. Differentiated cells were pretreated with MPEP, and hydrogen peroxide (H₂O₂). Our results revealed that treatment with MPEP before H₂O₂ treatment increased cell viability and decreased H₂O₂-induced lactate dehydrogenase (LDH) and creatine kinase (CK). In addition, MPEP attenuated H₂O₂-induced upregulation of Bax, downregulation of Bcl-2, and activation of caspase-9 and -3. These results suggest the MPEP can stimulate C2C12 muscle cell differentiation into myotubes and observe the protective effect of mixed plant-extract powder against muscle oxidative stress. In conclusion, MPEP may be useful as a prevention and treatment material for skeletal muscle disease caused by age-related diseases.

• International Journal of Oral Biology
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• v.36 no.2
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• pp.71-78
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• 2011

Using whole cell current- and voltage-clamp recording we investigated the characteristics and pharmacology of group I metabotropic glutamate receptor (mGluR)-mediated responses in rat medial vestibular nucleus (MVN) neurons. In current clamp conditions, activation of mGluR I by application of the group I mGluR agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) induced a direct excitation of MVN neurons that is characterized by depolarization and increased spontaneous firing frequency. To identify which of mGluR subtypes are responsible for the various actions of DHPG in MVN, we used two 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 that is selective for mGluR5. In voltage clamp conditions, DHPG application increased the frequency of spontaneous and miniature inhibitory postsynaptic currents (IPSCs) but had no effect on amplitude distributions. Antagonism of the DHPG-induced increase of miniature IPSCs required the blockade of both mGluR1 and mGluR5. DHPG application induced an inward current, which can be enhanced under depolarized conditions. DHPG-induced current was blocked by LY367385, but not by MPEP. Both LY367385 and MPEP antagonized the DHPG-induced suppression of the calcium activated potassium current ($I_{AHP}$). These data suggest that mGluR1 and mGluR5 have similar roles in the regulation of the excitability of MVN neurons, and show a little distinct. Furthermore, mGluR I, via pre- and postsynaptic actions, have the potential to modulate the functions of the MVN.

• International Journal of Oral Biology
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• v.34 no.4
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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.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.491-506
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• 2014

The purpose of this study is to examine the effect of expected perspective on the role of genre and attitude toward utilizing genre in broadcast ad on the liking of broadcast ad genre as appeal types of creativity. The results show that there is a significant correlation between macro-environmental expected perspective(MEEP) on the role of genre and a negative attitude toward utilizing genre in broadcast ad. A significant correlation between micro-practical expected perspective(MPEP) and a positive attitude was also found. Consumers with an integrated-situational expected perspective(ISEP) show a more significant relationship with the dual attitude. Consumes with a MPEP have a stronger liking on comparative ad and sex appeal ad, and consumers with an ISEP show a median liking. Consumers with positive attitude have a stronger liking on comparative ad and sex appeal ad, and consumers with a dual attitude show a median liking that is between the positive attitude-based consumers' and negative attitude-based consumers'.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.278-280
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• 2007

In this paper, wd design the Program Specific Information (PSI) parser and its On-Screen Display (OSD) on the middleware of ALi M3330 MPEG-2 decoder processor to analyze DVB-T Transport Stream(TS) information. To test the functional operation of the designed parser, we implement the DVB-T test board including the RF-tuner using ALi M3330 MPEP-2 decoder processor and confirm the correct operation using the input TS stream generated by DVB-T stream generator. The developed PSI parser could be used for the test environment, various channel extension, and the development of DVB-T reception module.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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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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• v.12 no.5
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• pp.237-243
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• 2008

Intraplantar injection of melittin has been known to induce sustained decrease of mechanical threshold and increase of spontaneous flinchings. The present study was undertaken to investigate how the melittin-induced nociceptive responses were modulated by changes of metabotropic glutamate receptor (mGluR) activity. Changes in paw withdrawal threshold (PWT), number of flinchings and paw thickness were measured at a given time point after injection of melittin ($10{\mu}g$/paw) into the mid-plantar area of rat hindpaw. To observe the effects of mGluRs on the melittin-induced nociceptions, group I mGluR (AIDA, $100{\mu}g$ and $200{\mu}g$), $mGluR_1$ (LY367385, $50{\mu}g$ and $100{\mu}g$) and $mGluR_5$ (MPEP, $200{\mu}g$ and $300{\mu}g$) antagonists, group II (APDC, $100{\mu}g$ and $200{\mu}g$) and III (L-SOP, $100{\mu}g$ and $200{\mu}g$) agonists were intrathecally administered 20 min before melittin injection. Intraplantar injection of melittin induced a sustained decrease of mechanical threshold, spontaneous flinchings and edema. The effects of melittin to reduce mechanical threshold and to induce spontaneous flinchings were significantly suppressed following intrathecal pre-administration of group I mGluR, $mGluR_1$ and $mGluR_5$ antagonists, group II and III mGluR agonists. Group I mGluR antagonists and group II and III mGluR agonists had no significant effect on melittin-induced edema. These experimental findings indicate that multiple spinal mGluRs are involved in the modulation of melittin-induced nociceptive responses.