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

J. J. Galligan, H. Tatsumi, Ke-Zhong Shen, A. Surprenant, R. A. North

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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)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume259
Issue number6 22-6
StatePublished - 1990

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Cations
Guinea Pigs
Neurons
Membrane Potentials
Potassium
Submucous Plexus
Cesium
Microelectrodes
Barium
Cobalt
Sodium
Ions
Calcium

Keywords

  • electrophysiology
  • enteric nervous system
  • gastrointestinal tract

ASJC Scopus subject areas

  • Physiology
  • Gastroenterology

Cite this

Cation current activated by hyperpolarization (I(H)) in guinea pig enteric neurons. / Galligan, J. J.; Tatsumi, H.; Shen, Ke-Zhong; Surprenant, A.; North, R. A.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 259, No. 6 22-6, 1990.

Research output: Contribution to journalArticle

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AU - North, R. A.

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