Activation of group I metabotropic glutamate receptors modulates descending activation of spinal cord motoneurons

Abstract

Abstract: AIM: To evaluate the modulatory action of group I metabotropic glutamate receptors (mGluRs) on descending activation of spinal cord motoneurons (MNs) in vitro.METHODS: The intracellular recordings were made in MNs of spinal cord slices isolated from neonatal rats (7-14 days old), and excitatory postsynaptic potential (EPSP) was evoked by ipsilateral ventrolateral funiculus (iVLF) stimulation, i.e. iVLF-EPSP.By superfusion of (S)-3,5-dihydroxyphenylglycine hydrate (DHPG), an agonist of group I mGluRs, the modulatory action was observed on the MN membrane electrical properties, as well as on the iVLF-EPSP.RESULTS: Application of DHPG (5 μmol/L) significantly depolarized the motoneuron membrane (n=7, P<0.01), reduced time constant (n=7, P<0.05), and extended the half-width of the spike potential (n=5, P<0.05). The amplitude of iVLF-EPSPs in 7 tested MNs was reversibly and concentration-dependently suppressed by superfusion of DHPG (5-10 μmol/L,P<0.01).CONCLUSION: Activation of group I mGluRs by DHPG may inhibit the descending activation of spinal cord MNs in vitro.

Key words: Motoneuron, Spinal cord, Metabotropic glutamate receptor, Descending activation, (S)-3,5-dihydroxyphenylglycine hydrate(DHPG)

CLC Number:

R965.2

ZHENG Yong, WANG Meng-ya. Activation of group I metabotropic glutamate receptors modulates descending activation of spinal cord motoneurons[J]. Chinese Journal of Clinical Pharmacology and Therapeutics, 2011, 16(12): 1374-1378.

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