Article date: 1992/8/21
PubMed ID: 1356659
Journal name: Brain research. Developmental brain research (ISSN: 0165-3806)
We have recently shown that a high-affinity AMPA receptor labelled with the antagonist [3H]CNQX can be regulated in a 'living' cortical slice preparation by agonist stimulation or changes in electrical activity (Lanius, R.A. and Shaw, C. (1992) Anat. Rec., in press). Based on a study of GABAA receptors (Shaw, C. and Scarth, B.A. (1992) Mol. Brain Res., in press), which showed age-dependent changes in regulation, we have now investigated the regulation of high-affinity AMPA receptors in neocortex at different stages in postnatal development. The results show that regulation by agonist stimulation and increases in bioelectric activity are age-dependent in amount and, in the latter case, in direction. Agonist stimulation using quisqualate resulted in a significant receptor down-regulation of approximately 7% at ages less than 20 days postnatal; in adult rats quisqualate led to a significant 23% decrease. Changes in bioelectric activity induced by a combination of veratridine and glutamate showed a significant increase in AMPA receptor number of 16% at ages less than 20 days, whereas such treatment resulted in a significant 18% decrease in adult rats. The present data reveal a near mirror-image to the effects of veratridine and glutamate and agonist on GABAA receptors in the same preparation, but with a temporal mismatch in the amount and direction of regulation. We speculate that the age-dependent differences in direction of regulation for the receptor populations which serve key excitatory and inhibitory functions in cortex may provide a molecular basis for the gradual decline of neuronal plasticity during the critical period.
Author List: Shaw C, Lanius R A
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Glutamates; Receptors, AMPA; Receptors, Amino Acid; Receptors, Neurotransmitter; Muscimol; Glutamic Acid; N-Methylaspartate; Veratridine; Quisqualic Acid; Kainic Acid;
Mesh terms: Aging/physiology; Animals; Cerebral Cortex/drug effects; Glutamates/pharmacology; Glutamic Acid; Kainic Acid/pharmacology; Male; Membrane Potentials/drug effects; Muscimol/pharmacology; N-Methylaspartate/pharmacology; Neuronal Plasticity/drug effects; Quisqualic Acid/pharmacology; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptors, AMPA; Receptors, Amino Acid/drug effects; Receptors, Neurotransmitter/drug effects; Veratridine/pharmacology;