Ghrelin reduces voltage-gated calcium currents in GH3 cells via cyclic GMP pathways

Han, Xuefeng, Zhu, Yunlong, Zhao, Yufeng and Chen, Chen (2011) Ghrelin reduces voltage-gated calcium currents in GH3 cells via cyclic GMP pathways. Endocrine, 40 2: 228-236. doi:10.1007/s12020-011-9520-z


Author Han, Xuefeng
Zhu, Yunlong
Zhao, Yufeng
Chen, Chen
Title Ghrelin reduces voltage-gated calcium currents in GH3 cells via cyclic GMP pathways
Formatted title
Ghrelin reduces voltage-gated calcium currents in GH3 cells
via cyclic GMP pathways
Journal name Endocrine   Check publisher's open access policy
ISSN 1355-008X
1559-0100
Publication date 2011
Sub-type Article (original research)
DOI 10.1007/s12020-011-9520-z
Volume 40
Issue 2
Start page 228
End page 236
Total pages 9
Place of publication Totowa, NJ, United States
Publisher Humana Press
Collection year 2012
Language eng
Formatted abstract
Ghrelin is an endogenous growth hormone secretagogue (GHS) causing release of GH from pituitary somatotropes through the GHS receptor. Secretion of GH is linked directly to intracellular free Ca2+ concentration ([Ca2+]i), which is determined by Ca2+ influx and release from intracellular Ca2+ storage sites. Ca2+ influx is via voltage-gated Ca2+ channels, which are activated by cell depolarization. The mechanism underlying the effect of ghrelin on voltage-gated Ca2+ channels is still not clear. In this report, using whole cell patch-clamp recordings, we assessed the acute action of ghrelin on voltage-activated Ca2+ currents in GH3 rat somatotrope cell line. Ca2+ currents were divided into three types (T, N, and L) through two different holding potentials (−80 and −40 mV) and specific L-type channel blocker (nifedipine, NFD). We demonstrated that ghrelin significantly and reversibly decreases all three types of Ca2+ currents in GH3 cells through GHS receptors on the cell membrane and down-stream signaling systems. With different signal pathway inhibitors, we observed that ghrelin-induced reduction in voltage-gated Ca2+ currents in GH3 cells was mediated by a protein kinase G-dependent pathways. As ghrelin also stimulates Ca2+ release and prolongs the membrane depolarization, this reduction in voltage-gated Ca2+ currents may not be translated into a reduction in [Ca2+]i, or a decrease in GH secretion.
Keyword Ghrelin
GH3 cells
Voltage-gated ca2+ channels
Protein kinase G
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biomedical Sciences Publications
 
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Created: Wed, 12 Oct 2011, 09:37:54 EST by Professor Chen Chen on behalf of School of Biomedical Sciences