Analysis of spontaneous electrical activity in cerebellar Purkinje cells acutely isolated from postnatal rats

Sang C. Nam, Philip E. Hockberger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Whole-cell patch recording techniques were used to analyze spontaneous electrical activity in cerebellar Purkinje cells acutely isolated from postnatal rats. Spontaneous activity was present in 65% of the cells examined, and it included simple and complex firing patterns which persisted under conditions that eliminated residual or reformed synaptic contacts. Under voltage clamp, both spontaneous and quiescent cells displayed similar voltage-dependent conductances. Inward current was carried by Na+ through tetrodotoxin (TTX)-sensitive channels and by Ca2+ through P-type and T- type Ca channels. P-type current was present in all cells examined. T-type current was found in <50%, and it did not correlate with spontaneous activity. We found no evidence of a transient (A-type) potassium current or hyperpolarization-activated cationic current in either spontaneons or quiescent cells. Spontaneous activity did correlate with a lower activation threshold of the Na current, resulting in substantial overlap of the activation and inactivation curves. TTX reduced the holding current of spontaneous cells clamped between -50 and -30 mV, consistent with the presence of a Na 'window' current. We were unable, however, to measure a persistent component of the Na current using voltage steps, a result which may reflect the complex goring properties of Na channels. An Na window current could provide the driving force underlying spontaneous activity, as well as plateau potentials, in Purkinje cells.

Original languageEnglish (US)
Pages (from-to)18-32
Number of pages15
JournalJournal of Neurobiology
Volume33
Issue number1
DOIs
StatePublished - Jul 1997

Keywords

  • Na current
  • Pacemaker activity
  • Persistent current
  • Purkinje cells
  • Repetitively firing
  • Window current

ASJC Scopus subject areas

  • Neuroscience(all)
  • Cellular and Molecular Neuroscience

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