Carbonic anhydrase isoform VII acts as a molecular switch in the development of synchronous gamma-frequency firing of hippocampal CA1 pyramidal cells.
Identification of the molecular mechanisms that enable synchronous firing of CA1 pyramidal neurons is central to the understanding of the functional properties of this major hippocampal output pathway. Using microfluorescence measurements of intraneuronal pH, in situ hybridization, as well as intracellular, extracellular, and K+-sensitive microelectrode recordings, we show now that the capability for synchronous gamma-frequency (20-80 Hz) firing in response to high-frequency stimulation (HFS) emerges abruptly in the rat hippocampus at approximately postnatal day 12. This was attributable to a steep developmental upregulation of intrapyramidal carbonic anhydrase isoform VII, which acts as a key molecule in the generation of HFS-induced tonic GABAergic excitation. These results point to a crucial role for the developmental expression of intrapyramidal carbonic anhydrase VII activity in shaping integrative functions, long-term plasticity and susceptibility to epileptogenesis.
Ruusuvuori
Eva
E
Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, University of Helsinki, FIN-00014 Helsinki, Finland.
Li
Hong
H
Huttu
Kristiina
K
Palva
J Matias
JM
Smirnov
Sergei
S
Rivera
Claudio
C
Kaila
Kai
K
Voipio
Juha
J
D000200:Action Potentials / Q000502:physiology; D000367:Age Factors; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D001683:Biological Clocks / Q000502:physiology; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography; D005110:Extracellular Space / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006624:Hippocampus / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D017966:Pyramidal Cells / Q000201:enzymology* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D001639:Bicarbonates; D007527:Isoenzymes; D005680:gamma-Aminobutyric Acid; D002256:Carbonic Anhydrases; D011188:Potassium