Two types of voltage-gated K channels in carotid body cells of adult cats

Chung Long Chou, Machiko Shirahata

Research output: Contribution to journalArticlepeer-review

Abstract

The purpose of this study was to investigate if the oxygen-sensitive K channel is present in the carotid body cells of adult cats, and if all carotid body cells express the oxygen-sensitive K channel. A standard patch-clamp technique with a whole-cell configuration was applied to cultured carotid body cells from adult cats. The cells were continuously perfused with Krebs equilibrated with 5% CO2/air or 5% CO2/argon at room temperature. The results showed that electrophysiologically at least two types of cells existed in cultured cat carotid body cells. One type expressed the oxygen-sensitive K channel and the other expressed the oxygen-insensitive K channel. The oxygen-sensitive K channel was voltage-dependent with a threshold potential of -30 mV. No inactivation was observed during 40 ms of stimulation. The slope of the steady-state current-voltage curve was almost linear in the range from -30 mV to +50 mV. Hypoxia (pO2 = 25 mmHg) reversibly depressed the K current by 22%. The current was inhibited by 4-aminopyridine (10 mM) and tetraethylammonium (4-25 mM), but insensitive to charybdotoxin (100 nM). The oxygen-insensitive K channel showed similar characteristics to that of the oxygen-sensitive K channel in the threshold and the speed of activation, and the shape of I-V curve. The cat is the third species in which the oxygen-sensitive K channel was found in the carotid body. The sensitivity of K channels to oxygen may be a unique feature of chemosensory cells, but the properties of the oxygen-sensitive K channels are different among cats, rats, and rabbits.

Original languageEnglish (US)
Pages (from-to)34-42
Number of pages9
JournalBrain research
Volume742
Issue number1-2
DOIs
StatePublished - Dec 2 1996

Keywords

  • K current
  • chemoreceptor
  • glomus cell
  • hypoxia
  • oxygen
  • sheath cell

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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