Details

Autor(en) / Beteiligte

• De Miera, Eleazar Vega-Saenz
• Rudy, Bernardo
• Sugimori, Mutsuyuki
• Llinás, Rodolfo

Titel

Molecular Characterization of the Sodium Channel Subunits Expressed in Mammalian Cerebellar Purkinje Cells

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 1997-06, Vol.94 (13), p.7059-7064

Ort / Verlag

United States: National Academy of Sciences of the United States of America

Erscheinungsjahr

1997

Quelle

MEDLINE

Beschreibungen/Notizen

• Inactivating and noninactivating Na+ conductances are known to generate, respectively, the rising phase and the prolonged plateau phase of cerebellar Purkinje cell (PC) action potentials. These conductances have different voltage activation levels, suggesting the possibility that two distinct types of ion channels are involved. Single Purkinje cell reverse transcription-PCR from guinea pig cerebellar slices identified two Na+ channel α subunit transcripts, the orthologs of RBI (rat brain I) and Nach6/Scn8a. The latter we shall name CerIII. In situ hybridization histochemistry in rat brain demonstrated broad CerIII expression at high levels in many neuronal groups in the brain and spinal cord, with little if any expression in white matter, or nerve tracts. RBII (rat brain II), the most commonly studied recombinant Na+ channel α subunit is not expressed in PCs. As the absence of Scn8a has been correlated with motor endplate disease (med), in which transient sodium currents are spared, RBI appears to be responsible for the transient sodium current in PC. Conversely, jolting mice with a mutated Scn8a message demonstrates PC abnormalities in rapid, simple spike generation, linking CerIII to the persistent sodium current.