Multiple components of Ca2+ channel facilitation in cerebellar granule cells: expression of facilitation during development in culture

H R Parri, J B Lansman

Research output: Contribution to journalArticlepeer-review

Abstract

The contribution of pharmacologically distinct Ca2+ channels to prepulse-induced facilitation was studied in mouse cerebellar granule cells. Ca2+ channel facilitation was measured as the percentage increase in the whole-cell current recorded during a test pulse before and after it was paired with a positive prepulse. The amount of facilitation was small in recordings made during the first few days in tissue culture but increased substantially after 1 week. L-type channels accounted for the largest proportion of facilitation in 1-week-old cells (60-70%), whereas N-type channels contributed very little (approximately 3%). The toxins omega-agatoxin IVa or omega-conotoxin MVIIC (after block of N-, L-, and P-type channels) each blocked a small percentage of facilitation (approximately 12 and 14%, respectively). Perfusion of cells with GTP-gamma-S enhanced the facilitation of N-type channels, whereas it inhibited of L-type channels. During development in vitro, the contribution of L-type channels to the whole-cell current decreased. Single-channel recordings showed the presence of 10 and 15 pS L-type Ca2+ channels in 1-d-old cells. After 1 week in culture, a approximately 25 pS L-type channel dominated recordings from cell-attached patches. Positive prepulses increased the activity of the 25 pS channel but not of the smaller conductance channels. The expression of Ca(2+) channel facilitation during development may contribute to changes in excitability that allow frequency-dependent Ca(2+) influx during the period of active synaptogenesis
Original languageEnglish
Pages (from-to)4890-902
Number of pages13
JournalJournal of Neuroscience
Volume16
Issue number16
DOIs
Publication statusPublished - 15 Aug 1996

Bibliographical note

Copyright © 1996 Society for Neuroscience. Articles are released under a Creative Commons Attribution License after a 6 months embargo

Keywords

  • Animals
  • Calcium Channels
  • Cell Aging
  • Cells, Cultured
  • Cerebellum
  • Dihydropyridines
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Mice
  • Neurons
  • Phosphorylation

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