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

Published

Journal Article

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 microM), 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 microM). Whole cell patch-clamp recordings showed a hyperpolarizing shift in reversal potential after exposure to either thapsigargin (8 microM) 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.

Full Text

Duke Authors

Cited Authors

  • Mangel, AW; Snow, ND; Misukonis, MA; Basavappa, S; Middleton, JP; Fitz, JG; Liddle, RA

Published Date

  • June 1, 1993

Published In

Volume / Issue

  • 264 / 6 Pt 1

Start / End Page

  • G1031 - G1036

PubMed ID

  • 8333529

Pubmed Central ID

  • 8333529

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajpgi.1993.264.6.G1031

Language

  • eng

Conference Location

  • United States