Hypotonic swelling increases L-type calcium current in smooth muscle cells of the human stomach

Chun Hee Kim, Poong Lyul Rhee, Jong Chul, Yong Il Kim, Insuk So, Ki Whan Kim, Myoung Kyu Park, Dae Yong Uhm, Tong Mook Kang

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

The purpose of the present study was to characterize the Ca2+ channels in smooth muscle cells from human stomach and to examine the effects of osmotic swelling on the channel activity. Ca2+ channel current with either Ca2+ or Ba2+ as charge carrier was recorded from freshly isolated smooth muscle cells using the conventional whole-cell patch clamp technique. The degree of cell swelling as a result of hypotonic challenge was monitored using a video image analysis system. The changes in intracellular Ca2+ concentration ([Ca2+](i)) were measured by microfluorimetry. The pharmacological and voltage activation profile suggests a typical dihydropyridine-sensitive L-type Ca2+ current. Cell swelling, induced by hypotonic challenge, enhanced the amplitude of currents through L-type Ca2+ channels without significant effects on steady-state voltage dependency. After treatment with the L-type Ca2+ channel agonist Bay K 8644 (0.1-2 μm), no further significant increase in calcium channel current or corresponding [Ca2+](i) transients were provoked by the swelling. The above results demonstrated that the presence of L-type Ca2+ current in smooth muscle cells of the human stomach and the augmentation of the current are closely associated with the volume increase resulting from hypotonic swelling.

Original languageEnglish (US)
Pages (from-to)497-504
Number of pages8
JournalExperimental Physiology
Volume85
Issue number5
DOIs
StatePublished - 2000
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)

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  • Cite this

    Kim, C. H., Rhee, P. L., Chul, J., Kim, Y. I., So, I., Kim, K. W., Park, M. K., Uhm, D. Y., & Kang, T. M. (2000). Hypotonic swelling increases L-type calcium current in smooth muscle cells of the human stomach. Experimental Physiology, 85(5), 497-504. https://doi.org/10.1017/s0958067000020133