Voltage-dependent gating of ATP-activated channels in PC12 cells

Ken Nakazawa, Min Liu, Kazuhide Inoue, Yasuo Ohno

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6 Citations (Scopus)

Abstract

The possibility that P2X receptors exhibit voltage-dependent gating in a similar manner to nicotinic receptors was investigated in rat pheochromocytoma cells with the use of whole cell voltage-clamp techniques. In the presence of extracellular ATP, slowly activating inward currents were elicited by stepping from -50 mV to potentials more negative than -80 mV; these currents had a time constant of ~60 ms at -120 mV. This slowly activating component (as a fraction of the total ATP-induced current) increased with membrane hyperpolarization from -80 to -100 mV and was much increased when depolarizing prepulses were applied, although the time constant of activation was not altered by depolarizations. The fraction of the slowly activating current and its time constant were decreased as the ATP concentration was increased from 10 to 300μM. Thus it has been demonstrated that voltage-dependent gating of ATP-activated channels does occur in PC12 cells, and that this gating is modified by agonist concentration. It is possible that such gating may serve as a postsynaptic mechanism to facilitate excitatory neurotransmission by contributing to the inward rectification of the ATP-activated currents.

Original languageEnglish
Pages (from-to)884-890
Number of pages7
JournalJournal of Neurophysiology
Volume78
Issue number2
DOIs
Publication statusPublished - Aug 1997
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Physiology

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