Ceramide inhibits the inwardly rectifying potassium current in GH3 lactotrophs

Sheng-Nan Wu, Yuk Keung Lo, Benjamin Ing Tiau Kuo, Hung Ting Chiang

Research output: Contribution to journalArticle

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Abstract

The effects of ceramide on ion currents in rat pituitary GH3 cells were investigated. Hyperpolarization-elicited K+ currents present in GH3 cells were studied to determine the effect of ceramide and other related compounds on the inwardly rectifying K+ current (IK(IR)). Ceramide (C2-ceramide) suppressed the amplitude of IK(IR) in a concentration-dependent manner, with an IC50 value of 5 μM. Ceramide caused a rightward shift in the midpoint for the activation curve of IK(IR). Pretreatment with PD-98059 (30 μM) or U-0126 (30 μM) did not prevent ceramide-mediated inhibition of IK(IR). However, the magnitude of ceramide-induced inhibition of IK(IR) was attenuated in GH3 cells preincubated with dithiothreitol (10 μM). TNFα (100 ng/g) also suppressed IK(IR). In the inside-out configuration, application of ceramide (30 μM) to the bath slightly suppressed the activity of large conductance Ca2+-activated K+ channels. Under the current clamp mode, ceramide (10 μM) increased the firing of action potentials. Cells that exhibited an irregular firing pattern were converted to those displaying a regular firing pattern after application of ceramide (10 μM). Ceramide also suppressed IK(IR) in neuroblastoma IMR-32 cells. Therefore, ceramide can produce a depressant effect on IK(IR). The blockade of this current by ceramide may affect cell function.

Original languageEnglish
Pages (from-to)4785-4794
Number of pages10
JournalEndocrinology
Volume142
Issue number11
DOIs
Publication statusPublished - 2001 Jan 1

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Lactotrophs
Ceramides
Potassium
Calcium-Activated Potassium Channels
Dithiothreitol
Neuroblastoma
Baths
Action Potentials
Inhibitory Concentration 50

All Science Journal Classification (ASJC) codes

  • Endocrinology

Cite this

Wu, Sheng-Nan ; Lo, Yuk Keung ; Kuo, Benjamin Ing Tiau ; Chiang, Hung Ting. / Ceramide inhibits the inwardly rectifying potassium current in GH3 lactotrophs. In: Endocrinology. 2001 ; Vol. 142, No. 11. pp. 4785-4794.
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Ceramide inhibits the inwardly rectifying potassium current in GH3 lactotrophs. / Wu, Sheng-Nan; Lo, Yuk Keung; Kuo, Benjamin Ing Tiau; Chiang, Hung Ting.

In: Endocrinology, Vol. 142, No. 11, 01.01.2001, p. 4785-4794.

Research output: Contribution to journalArticle

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