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Updated: Aug 18, 2026

Dissection of Local Ca2+ Signals in Cultured Cells by Membrane-targeted Ca2+ Indicators
Published on: March 22, 2019
Biophysical basis of pituitary cell type-specific Ca2+ signaling-secretion coupling
Stanko S Stojilkovic1, Hana Zemkova, Fredrick Van Goor
1Section on Cellular Signaling, Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, MD 20892-4510, USA. stankos@helix.nih.gov
Abstract:
All secretory pituitary cells exhibit spontaneous and extracellular Ca2+-dependent electrical activity. Somatotrophs and lactotrophs fire plateau-bursting action potentials, which generate Ca2+ signals of sufficient amplitude to trigger hormone release. Gonadotrophs also fire action potentials spontaneously, but as single, high-amplitude spikes with limited ability to promote Ca2+ influx and secretion. However, Ca2+ mobilization in gonadotrophs transforms single spiking into plateau-bursting-type electrical activity and triggers secretion. Patch clamp analysis revealed that somatotrophs and lactotrophs, but not gonadotrophs, express BK (big)-type Ca2+-controlled K+ channels, activation of which is closely associated with voltage-gated Ca2+ influx. Conversely, pituitary gonadotrophs express SK (small)-type Ca2+-activated K+ channels that are colocalized with intracellular Ca2+ release sites. Activation of both channels is crucial for plateau-bursting-type rhythmic electrical activity and secretion.
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