Comparison of Mg, Mn, and Co Ions Affecting the β-Adrenoceptor-Mediated Membrane Response in the Guinea-Pig Taenia Caeci

Keiji Maruta, Takuro Osa, Hiroyoshi Inoue

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Electrical activity was recorded intracellularly from the muscle cell of guinea-pig taenia caeci in Locke solution. Membrane potential was —46.4mV, and spike potentials were discharged spontaneously. Isoprenaline (3 μm) hyperpolarized the membrane and suppressed the spike discharge. The hyperpolarization by isoprenaline was increased at low K (2 mM), while decreased at high K (11.8, 29.5, 59 mm). The hyperpolarization by isoprenaline was potentiated in the presence of external Mg ions, depending on the concentration of Mg (0–9.6 mM). Forskolin (3 μm) and papaverine (30 μm) hyperpolarized the membrane; the effects were augmented by 1.2 mm Mg. The hyperpolarization in response to 3 μm isoprenaline or 100 μm papaverine was inhibited by Mn, Co, and low Ca (1 mm) whereas it was not affected by high Ca (7.5 mm). Verapamil (0.5, 2 μm) had no influence of the hyperpolarization caused by isoprenaline. It was discussed that extracellular and/or intracellular Mg and Ca ions played important roles in the β-adrenoceptor-mediated action on the smooth muscle membrane of taenia caeci.

Original languageEnglish
Pages (from-to)659-671
Number of pages13
JournalThe Japanese journal of physiology
Volume39
Issue number5
DOIs
Publication statusPublished - 1989
Externally publishedYes

Keywords

  • Mg
  • Mn
  • forskolin
  • guinea-pig taenia caeci
  • isoprenaline

ASJC Scopus subject areas

  • Physiology

Fingerprint

Dive into the research topics of 'Comparison of Mg, Mn, and Co Ions Affecting the β-Adrenoceptor-Mediated Membrane Response in the Guinea-Pig Taenia Caeci'. Together they form a unique fingerprint.

Cite this