Developmental changes in the susceptibility to long-term potentiation of neurones in rat visual cortex slices.

Article date: 1991/5/20

PubMed ID: 1680581

Journal name: Brain research. Developmental brain research (ISSN: 0165-3806)


We investigated with intracellular recordings from rat visual cortex slices whether the susceptibility to undergo long-term potentiation (LTP) is age-dependent and whether it is correlated with the expression of synaptic responses mediated by N-methyl-D-aspartate (NMDA) receptors. Test and tetanic stimuli were applied to the white matter and post-tetanic modifications of the amplitude of postsynaptic potentials (PSPs) were assessed in regular spiking cells of supragranular layers. At 2 weeks of age, the amplitudes of early (8-10 ms post-stimulus) and late (20 ms post-stimulus) PSP-components increased after tetanic stimulation to 137.1 +/- 13.4% and 141.3 +/- 12.1% of the pretetanic controls, respectively. At 3 weeks, potentiation of both PSP-components was less pronounced but still significant, the late component being on average more potentiated than the early one. At 4 weeks, PSPs were no longer potentiated. Bath application of 25 microM DL-2-amino-5-phosphonovalerate (APV), an NMDA receptor antagonist, blocked LTP induction both at 2 and at 3 weeks. We also studied developmental changes of two synaptic responses known to influence the susceptibility of cortical neurones to LTP, the NMDA receptor-mediated excitatory PSP (EPSP) and the initial inhibitory PSP (iIPSP). The amplitude of the APV-sensitive EPSP decreased with age and reached adult values in 4-week-old animals. The iIPSPs were pronounced already at 2 weeks and showed no marked change during further development. The results suggest a close correlation between the susceptibility to undergo LTP and the extent to which NMDA receptor-gated conductances contribute to the synaptic response.(ABSTRACT TRUNCATED AT 250 WORDS)

This document is available from: http://directlinks.cc/files/muscimol/1680581.pdf

Author List: Kato N, Artola A, Singer W

Publication Types: Journal Article; Research Support, Non-U.S. Gov't

Substances mentioned in the article: Quinoxalines; Receptors, N-Methyl-D-Aspartate; Ibotenic Acid; 6-Cyano-7-nitroquinoxaline-2,3-dione; 2-Amino-5-phosphonovalerate; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

Mesh terms: 2-Amino-5-phosphonovalerate/pharmacology; 6-Cyano-7-nitroquinoxaline-2,3-dione; Aging/physiology; Animals; Electric Stimulation; Evoked Potentials/physiology; Ibotenic Acid/analogs & derivatives; In Vitro Techniques; Membrane Potentials/drug effects; Neurons/drug effects; Quinoxalines/pharmacology; Rats; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors; Synapses/drug effects; Visual Cortex/cytology; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

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