Actions of Group I Metabotropic Glutamate Receptor Agonist on Synaptic Transmission and Ionic Currents in Rat Medial Vestibular Nucleus Neurons
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Medial vestibular nucleus (MVN) neurons are involved inthe reflex control of the head and eyes, and in the recovery ofvestibular function after the formation of peripheral vestibularlesions. In our present study, whole cell patch clamprecordings were carried out on MVN neurons in brainstemslices from neonatal rats to investigate the actions of a groupI metabotropic glutamate receptor (mGluR) agonist uponsynaptic transmission and ionic currents. Application of themGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG)increased the frequency of miniature inhibitory postsynapticcurrents (mIPSCs) but had no effect upon amplitudedistributions. To then identify which of mGluR subtypes isresponsible for the actions of DHPG in the MVN, weemployed two novel subtype selective antagonists. (S)-(+)-α-amino-a-methylbenzeneacetic acid (LY367385) is a potentcompetitive antagonist that is selective for mGluR1, whereas2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potentnoncompetitive antagonist of mGluR5. Both LY367385 andMPEP antagonized the DHPG-induced increase ofmIPSCs, with the former being more potent. DHPG wasalso found to induce an inward current, which can beenhanced under depolarized conditions. This DHPGinducedcurrent was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed bythe PLC blocker U-73122, the IP3 receptor antagonist 2-APB, and following the depletion of the intracellular Ca2+pool by thapsigargin. These data suggest that the DHPGinducedinward current may be mainly regulated by theintracellular Ca2+store via the PLC-IP3 pathway. Inconclusion, mGluR I, via pre- and postsynaptic actions, maymodulate the excitability of the MVN neurons.
Abstract
Medial vestibular nucleus (MVN) neurons are involved inthe reflex control of the head and eyes, and in the recovery ofvestibular function after the formation of peripheral vestibularlesions. In our present study, whole cell patch clamprecordings were carried out on MVN neurons in brainstemslices from neonatal rats to investigate the actions of a groupI metabotropic glutamate receptor (mGluR) agonist uponsynaptic transmission and ionic currents. Application of themGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG)increased the frequency of miniature inhibitory postsynapticcurrents (mIPSCs) but had no effect upon amplitudedistributions. To then identify which of mGluR subtypes isresponsible for the actions of DHPG in the MVN, weemployed two novel subtype selective antagonists. (S)-(+)-α-amino-a-methylbenzeneacetic acid (LY367385) is a potentcompetitive antagonist that is selective for mGluR1, whereas2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potentnoncompetitive antagonist of mGluR5. Both LY367385 andMPEP antagonized the DHPG-induced increase ofmIPSCs, with the former being more potent. DHPG wasalso found to induce an inward current, which can beenhanced under depolarized conditions. This DHPGinducedcurrent was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed bythe PLC blocker U-73122, the IP3 receptor antagonist 2-APB, and following the depletion of the intracellular Ca2+pool by thapsigargin. These data suggest that the DHPGinducedinward current may be mainly regulated by theintracellular Ca2+store via the PLC-IP3 pathway. Inconclusion, mGluR I, via pre- and postsynaptic actions, maymodulate the excitability of the MVN neurons.
참고문헌 (49)
- Awad H, "Activation of metabotropic glutamate receptors 5 has direct excitatory effects and potentiates NMDA receptor current in neurons of the subthalamic nucleus", J Neurosci, 20, pp.7871~7879 (2000)
- Anwyl R, "Metabotropic glutamate receptors : electrophysiological properties and role in plasticity", Brain Res Rev, 29, pp.83~120 (1999)
- Bashir ZI, "On long-term depression induced by activation of G-protein coupled receptors", Neurosci Res, 45, pp.363~367 (2003)
- Bevan MD, "Mechanisms underlying spontaneous oscillation and rythmic firing in rat subthalamic neurons", J Neurosci, 19, pp.7617~7628 (1999)
- Bortolotto ZA, "Roles of metabotropic glutamate receptors in LTP and LTD in the hippocampus", Curr Opin Neurobiol, 9, pp.299~304 (1999)
- Brailoiu E, "Inositol trisphosphate and cyclic adenosine diphosphate-ribose increase quantal transmitter release at frog motor nerve terminals: possible involvement of smooth endoplasmic reticulum", Neurosci, 95, pp.927~931 (2000)
- Charpak S, "Potassium conductances in hippocampal neurons blocked by excitatory amino acid transmitters", Nature, 347, pp.765~767 (1990)
- Chuang SC, "mGluR activation turns on a voltage-gated inward current in hippocampal pyramidal cells", J Neurophysiol, 83, pp.2844~2853 (2000)
- Chun SW, "Characterization of spontaneous synaptic transmission in rat medial vestibular nucleus", Neuroreport, 14, pp.1485~1488 (2003)
- Chun SW, "Distinct roles of metabotropic glutamate receptors 1 and 5 in rat medial vestibular nucleus neurons", Kor J Physiol Pharmacol, 8, pp.s69~ (2004)
- Conn PJ, "Pharmacology and functions of metabotropic glutamate receptors", Ann Rev Pharmac Toxicol, 37, pp.205~237 (1997)
- Crepel V, "Glutamate metabotropic receptors increase a Ca 2+ -activated nonspecific cationic current in CA1 hippocampal neurones", Br J Pharmacol, 116, pp.1859~1869 (1994)
- Darlington CL, "Metabotropic glutamate receptors in the guinea pig medial vestibular nucleus in vitro", Neuroreport, 6, pp.1799~1802 (1995)
- Empson RM, "Cyclic ADP-ribose enhances coupling between voltage-gated Ca 2+ entry and intracellular Ca 2+ release", J Biol Chem, 272, pp.20967~20970 (1997)
- Fagni L, "Complex interactions between mGluRs, intracellular Ca 2+ stores and ion channels in neurons", Trends in Neurosci, 23, pp.80~88 (2000)
- Finch EA, "Local calcium signalling by inositol- 1,4,5-triphosphate in Purkinje cell dendrites", Nature, 396, pp.753~756 (1998)
- Gereau RW, "Roles of specific metabotropic glutamate receptor subtypes in regulation of hippocampal CA1 pyramidal cell excitability", J Neurophysiol, 74, pp.122~129 (1995)
- Grassi S, "Different metabotropic glutamate receptors play opposite roles in synaptic plasticity of the rat medial vestibular nuclei", J Physiol, 543, pp.795~806 (2002)
- Guerineau NC, "Reduction of resting K + current by metabotropic glutamate and muscarinic receptors in rat CA3 cells: mediation by G-proteins", J Physiol, 474, pp.27~33 (1994)
- Hirono M, "Phospholipase Cindependent group I metabotropic glutamate receptor-mediated inward current in mouse Purkinje cell", Biochem Biophys Res Commun, 251, pp.753~758 (1998)
- Horii A, "Quantitative changes in gene expression of glutamate receptor subunit", subtype in the vestibular nucleus, inferior olive and flocculus before and following unilateral labyrinthectomy in the rat: real-time quantitative PCR method, 2001, pp.139, 188~200
- Ireland DR, "Group I mGluRs increase excitability of hippocampal CA1 pyramidal neurons by a PLC-independent mechanism", J Neurophysiol, 88, pp.107~116 (2002)
- Kawabata S, "Control of calcium oscillations by phosphorylation of metabotropic glutamate receptors", Nature, 383, pp.89~92 (1996)
- Kettunen P, "mGluR1, but not mGluR5, mediates depolarization of spinal cord neurons by blocking a leak current", J Neurophysiol, 90, pp.2341~2348 (2003)
- Kinney GA, "The synaptic activation of N-methyl-D-aspartate receptors in the rat medial vestibular nucleus", J Neurophysiol, 72, pp.1588~1595 (1994)
- Lee K, "Characterization of the inward current induced by metabotropic glutamate receptor stimulation in rat ventromedial hypothalamic neurones", J Physiol, 504, pp.649~663 (1997)
- Llano I, "Presynaptic metabotropic glutamatergic regulation of inhibitory synapses in rat cerebellar slices", J Physiol, 486, pp.163~176 (1995)
- Luthi A, "A slowly inactivating potassium current in CA3 pyramidal cells of rat hippocampus in vitro", J Neurosci, 16, pp.586~594 (1996)
- Luthi A, "1S, 3R-ACPD induces a region of negative slope conductance in the steady-state current voltage relationship of hippocampal pyramidal cells", J Neurophysiol, 77, pp.221~228 (1997)
- Morikawa H, "Two intracellular pathways mediate metabotropic glutamate receptor-induced Ca 2+ mobilization in dopamine neurons", J Neurosci, 23, pp.149~157 (2003)
- Marino MJ, "Direct excitation of GABAergic projection neurons of the rat substantia nigra pars reticulata by activation of the mGluR1 metabotropic glutamate receptor", Soc Neurosci Abstr, 14, pp.4433~4445 (1999)
- pentyl)-glycine (CBPG), a novel mGlu5 receptor agonist endowed with mGlu1 receptor antagonist activity, "Neuropharmacol", 1999, 917~926
- Mothet JP, "Cyclic ADP-ribose and calcium-induced calcium release regulate neurotransmitter release at a cholinergic synapse of Aplysia", J Physiol, 507, pp.405~414 (1998)
- Mannaioni G, "Metabotropic glutamate receptors 1 and 5 differentially regulate CA1 pyramidal cell function", J Neurosci, 21, pp.5925~5934 (2001)
- Nakamura T, "Inositol 1,4,5-trisphosphate (IP3)- mediated Ca 2+ release evoked by metabotropic agonists and backpropagating action potentials in hippocampal CA1 pyramidal neurons", J Neurosci, 20, pp.8365~8376 (2003)
- Neki A, "Pre- and postsynaptic localization of a meta botropic glutamate receptor, mGluR2, in the rat brain : an immunohistochemical study with a monoclonal antibody", Neurosci Lett, 202, pp.197~200 (1996)
- Parekh AB, "Store depletion and calcium influx", Physiol Rev, 77, pp.901~930 (1997)
- Park HY, "Roles of metabotropic glutamate receptors in inhibitory synaptic transmission in rat medial vestibular nucleus neurons", J Korean Neurol Assoc, 21, pp.273~282 (2003)
- Petersen OH, "New Ca 2+ -releasing messengers: are they important in the nervous system?", Trends Neurosci, 22, pp.488~495 (1999)
- Pin JP, "Get receptive to metabotropic glutamate receptors", Curr Opin Neurobiol, 5, pp.342~349 (1995)
- Pin JP, "The metabotropic glutamate receptors: structure and functions", Neuropharmacol, 34, pp.1~26 (1997)
- Poncer JC, "Dual modulation of synaptic inhibition by distinct metabotropic glutamate receptors in the rat hippocampus", J Physiol, 485, pp.121~134 (1995)
- Rae MG, "Both mGluR1 and mGluR5 mediate Ca 2+ release and inward currents in hippocampal CA1 pyramidal neurons", Neuropharmacol, 46, pp.1057~1069 (2004)
- Shigemoto R, "Distribution of the mRNA for a metabotropic glutamate receptor (mGluR1) in the central nervous system : an in situ hybridization study in the adult and developing rat", J Comp Neurol, 322, pp.121~135 (1992)
- Smith PF, "Mechanisms of recovery following unilateral labyrinthectomy : a review", Brain Res Rev, 14, pp.155~180 (1989)
- Stefani A, "Activation of metabotropic glutamate receptors inhibits calcium currents and GABA-mediated synaptic potentials in striatal neurons", J Neurosci, 14, pp.6734~6743 (1994)
- Valenti O, "Distinct physiological roles of the Gq-coupled metabotropic glutamate receptors coexpressed in the same neuronal populations", J Cell Physiol, 191, pp.125~137 (2002)
- Vidal PP, "Intrinsic physiological and pharmacological properties of central vestibular neurons", Adv Otolaryngol, 55, pp.26~81 (1999)
- Zhou FM, "Metabotropic glutamate receptor enhancement of spontaneous IPSCs in neocortical interneuron", J Neurophysiol, 78, pp.2287~2295 (1997)
