Modulation of the Spontaneous Synaptic Activity of Tortoise Spinal Motoneurons by Group-II Metabotropic Glutamate Receptors

被引：0
作者：
V. M. Kozhanov
O. A. Karamian
N. M. Chmykhova
H.-P. Clamann
机构：
[1] Sechenov Institute of Evolutionary Physiology and Biochemistry,Russian Academy of Sciences
[2] Bern University,Institute of Physiology
来源：
Neurophysiology | 2001年 / 33卷
关键词：
tortoise; spinal motoneurons; spontaneous synaptic potentials; metabotropic glutamate receptors; neuromodulation;
D O I：
暂无
中图分类号：
学科分类号：
摘要：
We examined the effects of antagonists and an agonist of the metabotropic glutamate receptors (mGluR) on the frequency and amplitude of spontaneous postsynaptic potentials (PSP) and of a miniature fraction of these potentials in the lumbar segments of the spinal cord of the steppe tortoise (in 2- to 3-mm-thick superfused slices). We demonstrated that a common antagonist of the group-I and group-II mGluR, (+)MCPG (400 μM), as well as selective antagonists, MCCG (200 μM) and EGLU (100-200 μM), and a selective agonist of the group-II, DCG IV (1 μM), change the frequency of spontaneous PSP, including miniature PSP, but practically do not influence their amplitude. This feature shows that mGluR are presynaptically localized both in premotoneuronal links and immediately in synaptic contacts on the motoneurons. Comparison of the effects of antagonists of the mGluR on the normal synaptic activity and on that under conditions of the GABA receptor blockade shows that mGluR are involved in modulation of both glutamatergic and GABA-ergic transmission. We surmise that the NMDA reception plays a special role in the realization of mGluR-mediated modulating effects. The directions of the effects of the above antagonists and an agonist of the mGluR (an increase and a decrease in the frequency of synaptic potentials, respectively) allow us to postulate that the presynaptically localized group-II mGluR causes a decrease in the probability of release of excitatory and inhibitory transmitters in spinal synaptic structures of the tortoise.
引用
收藏
页码：98 / 105
页数：7
相关论文
共 85 条
  • [1] Tanabe Y.(1992)A family of metabotropic glutamate receptors Neuron 8 1-20
  • [2] Masu M.(1995)The metabotropic glutamate receptors: structure and functions Neuropharmacology 34 1-26
  • [3] Ishii T.(1997)Pharmacology and function of metabo-tropic glutamate receptors Annu. Rev. Pharmacol. Toxicol. 37 205-237
  • [4] Pin J.-P.(1997)Organization of glutamate receptors at the synapse Eur. J. Neurosci. 9 2219-2224
  • [5] Duvoisin R.(1996)The metabotropic glutamate receptors, mGluR2 and mGluR3, show unique postsynaptic, presynaptic and glial localizations Neuroscience 71 949-976
  • [6] Conn P. J.(1999)Metabotropic glutamate receptors: electrophysiological properties and role in p”sticity Brain Res. Rev. 29 83-120
  • [7] Pin J.-P.(1997)Modulation of plateau properties in dorsal horn neurones in a slice preparation of the turtle spinal cord J. Physiol. 499 459-454
  • [8] Ottersen O. P.(1997)Metabo-tropic synaptic regu”tion of intrinsic response properties of turtle spinal motoneurones J. Physiol. 504 97-102
  • [9] Lendsend A. S.(1998)Transmitter regulation of plateau properties in turtle motoneurons J. Neurophysiol. 79 45-50
  • [10] Petral R. S.(1988)Response properties of motoneurones in a slice preparation of the turtle spinal cord J. Physiol. 398 575-589
123456789