|
|
||||||||
The Journal of Neurophysiology Vol. 86 No. 1 July 2001, pp. 123-129
Copyright ©2001 by the American Physiological Society
Department of Neurobiology and Behavior, SUNY at Stony Brook, Stony Brook, New York 11794-5230
Arvanian, Victor L. and
Lorne M. Mendell.
Removal of NMDA Receptor Mg2+ Block Extends the
Action of NT-3 on Synaptic Transmission in Neonatal Rat
Motoneurons. J. Neurophysiol. 86: 123-129, 2001. NT-3 has previously been reported to enhance AMPA/kainate
receptor-mediated synaptic responses in motoneurons via an effect on
the N-methyl-D-aspartate (NMDA) receptor. To
investigate neurotrophin-3 (NT-3) action further, we measured the NMDA
receptor (NMDAR)-mediated synaptic response directly by intracellular
recording in motoneurons after blocking AMPA/kainate,
GABAA, GABAB and glycine
receptor-mediated responses pharmacologically. Two pathways were
stimulated, the segmental dorsal root (DR) and the descending
ventrolateral fasciculus (VLF). The DR-evoked NMDAR-mediated response
in motoneurons of rats younger than 1 wk has two components, the
initial one of which is generated monosynaptically. NT-3 strongly
potentiated both NMDA components in a rapidly reversible manner. No
NMDAR-mediated responses were present at VLF connections and at DR
connections in older (1- to 2-wk-old) neonates. Bath-applied
NT-3-induced potentiation of the AMPA/kainate receptor-mediated
response occurred only at connections that exhibit a synaptic NMDA
receptor-mediated response. Reducing Mg2+
concentration in the bathing solution restored the NMDAR-mediated response elicited by DR stimulation in older neonates and by VLF throughout the neonatal period (0-2 wk). In
low-Mg2+, NT-3 enhanced AMPA/kainate
receptor-mediated responses elicited by inputs normally not influenced
by NT-3. Thus a major reason for the loss of NT-3 action on
AMPA/kainate synaptic responses is the reduced activity of the NMDA
receptor due to developing Mg2+ block of NMDA
receptor-channel complex as the animal matures, and both can be
re-established by reducing Mg2+ concentration in
fluid bathing the spinal cord.
This article has been cited by other articles:
![]() |
M. Kron, M. Morschel, J. Reuter, W. Zhang, and M. Dutschmann Developmental changes in brain-derived neurotrophic factor-mediated modulations of synaptic activities in the pontine Kolliker Fuse nucleus of the rat J. Physiol., August 15, 2007; 583(1): 315 - 327. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. A. Crozier, Y. Wang, C.-H. Liu, and M. F. Bear Deprivation-induced synaptic depression by distinct mechanisms in different layers of mouse visual cortex PNAS, January 23, 2007; 104(4): 1383 - 1388. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. L. Arvanian, V. Motin, and L. M. Mendell Comparison of Metabotropic Glutamate Receptor Responses at Segmental and Descending Inputs to Motoneurons in Neonatal Rat Spinal Cord J. Pharmacol. Exp. Ther., February 1, 2005; 312(2): 669 - 677. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Frank Modulation of Synaptic Strength: Subunit Expression Controls the Critical Period. Focus on "Viral Delivery of NR2D Subunits Reduces Mg2+ Block of NMDA Receptors and Restores NT-3-Induced Potentiation of AMPA-Kainate Responses in Maturing Rat Motoneurons" J Neurophysiol, October 1, 2004; 92(4): 1971 - 1972. [Full Text] [PDF] |
||||
![]() |
V. L. Arvanian, W. J. Bowers, J. C. Petruska, V. Motin, H. Manuzon, W. C. Narrow, H. J. Federoff, and L. M. Mendell Viral Delivery of NR2D Subunits Reduces Mg2+ Block of NMDA Receptor and Restores NT-3-Induced Potentiation of AMPA-Kainate Responses in Maturing Rat Motoneurons J Neurophysiol, October 1, 2004; 92(4): 2394 - 2404. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. L. Arvanian, P. J. Horner, F. H. Gage, and L. M. Mendell Chronic Neurotrophin-3 Strengthens Synaptic Connections to Motoneurons in the Neonatal Rat J. Neurosci., September 24, 2003; 23(25): 8706 - 8712. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |