Irreversible loss of a subpopulation of cortical interneurons in the absence of glutamatergic network activity.
In the cerebral cortex of mammals, gamma-aminobutyric acid (GABA)ergic neurons represent 15-25% of all neurons, depending on the species and area being examined. Because converging evidence suggests that activity may play an important role in the neuritic maturation and synaptic function of GABAergic neurons, it is feasible that activity plays a role in the regulation of the proportion of GABAergic neurons. Here we provide direct evidence that early in cortical development activity blockade may deplete the network of a subpopulation of GABA immunoreactive neurons characterized by their small size and late generation in vitro. In a period of time coinciding with the emergence of synchronous network activity, the survival and morphological differentiation of GABAergic neurons was influenced by long-term blockade of synaptic activity. While GABA(A) receptor antagonists had a minor promoting effect on interneuronal survival during the second week in vitro, antagonists of ionotropic glutamate receptors strongly impaired survival and differentiation of immature GABAergic interneurons. Interneuronal loss was more severe when N-methyl-D-aspartate receptors were blocked than after blockade of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA)/kainate receptors. The decrease in the density of GABAergic neurons was irreversible, but could be prevented by the simultaneous addition of brain-derived neurotrophic factor (BDNF). These results suggest that there is a narrow time window during neocortical development when glutamatergic activity, and specially NMDA receptor stimulation, is crucial to assure survival and maturation of a subpopulation of late developing GABAergic interneurons.
de Lima
Ana Dolabela
AD
Otto-von-Guericke Universität, Medizinische Fakultät, Institut für Physiologie, 39120 Magdeburg, Germany. ana.delima@medizin.uni-magdeburg.de
Opitz
Thoralf
T
Voigt
Thomas
T
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001640:Bicuculline / Q000031:analogs & derivatives* / Q000494:pharmacology; D064032:Calbindin 2; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D004347:Drug Interactions; D004622:Embryo, Mammalian; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D007395:Interneurons / Q000145:classification / Q000166:cytology* / Q000378:metabolism; D009415:Nerve Net / Q000166:cytology / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013997:Time Factors; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D001640:Bicuculline; D064032:Calbindin 2; D002118:Calcium; D002135:Calcium-Binding Proteins; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D018698:Glutamic Acid; D010320:Parvalbumins; D010852:Picrotoxin; D064030:S100 Calcium Binding Protein G; D014633:Valine; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D005680:gamma-Aminobutyric Acid; C017069:bicuculline methiodide; C056639:2-amino-5-phosphopentanoic acid