Calcium-dependent regulation of cholecystokinin secretion and potassium currents in STC-1 cells

A. W. Mangel, N. D. Snow, M. A. Misukonis, S. Basavappa, J. P. Middleton, J. G. Fitz, R. A. Liddle

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

Secretory and electrophysiological properties of STC-1 cells, a cholecystokinin-secreting cell line, were examined with a radioimmunoassay and patch-clamp recording techniques. Stimulation of cholecystokinin secretion was seen after exposure to agents anticipated to increase the level of intracellular calcium, including thapsigargin (8 μM), bombesin (50 nM), potassium-induced depolarization (50 mM), or after blockade of potassium channels with barium chloride (2 mM). The secretory effects of these agents were blocked by pretreatment with the calcium channel blocker diltiazem (1 μM). Whole cell patch-clamp recordings showed a hyperpolarizing shift in reversal potential after exposure to either thapsigargin (8 μM) or bombesin (50 nM) from a control value of -27 ± 3 to -57 ± 7 or -48 ± 6 mV, respectively. This shift was in the direction of the reversal potential for potassium and was blocked by barium chloride (5 mM). Single-channel recordings from cell-attached membrane patches showed an inwardly rectifying potassium channel with channel open probability modulated by bombesin. These results indicate that in STC-1 cells a potassium current is increased by agents that stimulate CCK secretion, presumably by increasing the level of cytosolic calcium. STC-1 cells may serve as a model system to study the electrophysiological and secretory mechanisms involved in the release of cholecystokinin.

Original languageEnglish (US)
Pages (from-to)G1031-G1036
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume264
Issue number6 27-6
StatePublished - Jul 23 1993

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Keywords

  • gastrointestinal hormone
  • ion channel
  • patch clamp
  • radioimmunoassay

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

Cite this

Mangel, A. W., Snow, N. D., Misukonis, M. A., Basavappa, S., Middleton, J. P., Fitz, J. G., & Liddle, R. A. (1993). Calcium-dependent regulation of cholecystokinin secretion and potassium currents in STC-1 cells. American Journal of Physiology - Gastrointestinal and Liver Physiology, 264(6 27-6), G1031-G1036.