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Enhanced activation of NMDA receptor responses at the immature retinogeniculate synapse.
J Neurosci. 1994 Apr; 14(4):2098-105.JN

Abstract

The maturation of retinogeniculate excitatory transmission and intrathalamic inhibition was studied in slices of the dorsal LGN obtained from ferrets during the first 2 postnatal months. Response to optic tract stimulation at neonatal ages consisted of slow EPSPs lasting several hundred milliseconds. Application of the NMDA receptor antagonist D-(-)-2-amino-5-phosphonovaleric acid (D-APV) during the first 2 postnatal weeks resulted in EPSPs that were reduced in peak amplitude and dramatically curtailed in duration, indicating that NMDA receptors participate strongly in retinogeniculate transmission at the immature synapse. Gradually, EPSPs became shorter in duration such that after the second postnatal week, the retinogeniculate EPSPs were only a few milliseconds in duration. At this late stage of development responses were remarkably less affected by application of D-APV. These changes in contribution of NMDA receptors to retinogeniculate transmission were found to be due to the development of strong IPSPs, the result of gradual maturation of activation of GABAergic inhibition. Indeed, application of bicuculline methiodide to block GABAA receptor-mediated IPSPs strongly enhanced the NMDA component of the EPSPs in more mature cells. The voltage dependence and kinetics of NMDA-induced excitatory postsynaptic currents (NMDA EPSCs) were characterized by voltage-clamp recordings after blocking AMPA/kainate receptors with 6-cyano-7-nitroquinoxaline-2,3-dione and GABAA receptors wit' bicuculline methiodide. The voltage dependence of the NMDA EPSCs remained unaltered with age. During the first postnatal month the kinetic properties of the NMDA EPSCs also remained unaltered, but a reduction in EPSC duration was observed within the following weeks, well after the critical period of anatomical reorganization.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Section of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7908957

Citation

Ramoa, A S., and D A. McCormick. "Enhanced Activation of NMDA Receptor Responses at the Immature Retinogeniculate Synapse." The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, vol. 14, no. 4, 1994, pp. 2098-105.
Ramoa AS, McCormick DA. Enhanced activation of NMDA receptor responses at the immature retinogeniculate synapse. J Neurosci. 1994;14(4):2098-105.
Ramoa, A. S., & McCormick, D. A. (1994). Enhanced activation of NMDA receptor responses at the immature retinogeniculate synapse. The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, 14(4), 2098-105.
Ramoa AS, McCormick DA. Enhanced Activation of NMDA Receptor Responses at the Immature Retinogeniculate Synapse. J Neurosci. 1994;14(4):2098-105. PubMed PMID: 7908957.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Enhanced activation of NMDA receptor responses at the immature retinogeniculate synapse. AU - Ramoa,A S, AU - McCormick,D A, PY - 1994/4/1/pubmed PY - 1994/4/1/medline PY - 1994/4/1/entrez SP - 2098 EP - 105 JF - The Journal of neuroscience : the official journal of the Society for Neuroscience JO - J Neurosci VL - 14 IS - 4 N2 - The maturation of retinogeniculate excitatory transmission and intrathalamic inhibition was studied in slices of the dorsal LGN obtained from ferrets during the first 2 postnatal months. Response to optic tract stimulation at neonatal ages consisted of slow EPSPs lasting several hundred milliseconds. Application of the NMDA receptor antagonist D-(-)-2-amino-5-phosphonovaleric acid (D-APV) during the first 2 postnatal weeks resulted in EPSPs that were reduced in peak amplitude and dramatically curtailed in duration, indicating that NMDA receptors participate strongly in retinogeniculate transmission at the immature synapse. Gradually, EPSPs became shorter in duration such that after the second postnatal week, the retinogeniculate EPSPs were only a few milliseconds in duration. At this late stage of development responses were remarkably less affected by application of D-APV. These changes in contribution of NMDA receptors to retinogeniculate transmission were found to be due to the development of strong IPSPs, the result of gradual maturation of activation of GABAergic inhibition. Indeed, application of bicuculline methiodide to block GABAA receptor-mediated IPSPs strongly enhanced the NMDA component of the EPSPs in more mature cells. The voltage dependence and kinetics of NMDA-induced excitatory postsynaptic currents (NMDA EPSCs) were characterized by voltage-clamp recordings after blocking AMPA/kainate receptors with 6-cyano-7-nitroquinoxaline-2,3-dione and GABAA receptors wit' bicuculline methiodide. The voltage dependence of the NMDA EPSCs remained unaltered with age. During the first postnatal month the kinetic properties of the NMDA EPSCs also remained unaltered, but a reduction in EPSC duration was observed within the following weeks, well after the critical period of anatomical reorganization.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0270-6474 UR - https://www.unboundmedicine.com/medline/citation/7908957/Enhanced_activation_of_NMDA_receptor_responses_at_the_immature_retinogeniculate_synapse_ L2 - http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=7908957 DB - PRIME DP - Unbound Medicine ER -