Cation current activated by hyperpolarization (I(H)) in guinea pig enteric neurons

J. J. Galligan, H. Tatsumi, K. Z. Shen, A. Surprenant, R. A. North

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Intracellular microelectrode and whole cell patch-clamp recordings were made from guinea pig enteric neurons in vitro. In most myenteric AH neurons (but not S neurons), step hyperpolarizations from the resting potential evoked an inward current (I(H)). I(H) peaked in ~400 ms (at 36° C), was fully activated at -100 mV, and did not inactivate during 10 s. I(H) was associated with a conductance increase and reversed polarity at about -40 mV (by extrapolation). I(H) was reduced in low-sodium concentrations and increased when the concentration of extracellular potassium ions was increased. Cesium (2 mM) blocked I(H) in a voltage-dependent manner; this led to an increase in the amplitude of the spike after-hyperpolarization. Cobalt (2-4 mM) or barium (0.01-1 mM) did not alter I(H). Only 12% of submucous plexus neurons showed I(H) and this subgroup included both S and AH neurons. In myenteric AH neurons, I(H) would act in opposition to the persistent calcium-activated potassium current and thus stabilize the resting potential.

Original languageEnglish (US)
Pages (from-to)G966-G972
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume259
Issue number6 22-6
StatePublished - Dec 1 1990

Keywords

  • electrophysiology
  • enteric nervous system
  • gastrointestinal tract

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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