Abstract
We have pharmacologically characterized voltage sensitive calcium channels (VSCCs) in GH3 cells, an anterior pituitary clonal cell line known to secrete prolactin and growth hormone. Raising the medium K+ concentration from 5 to 50 mM caused an immediate increase in net 45Ca2+ uptake which remained apparent over a 15 minute time course. 45Ca2+ uptake was maximally stimulated nearly 10-fold over basal levels. This K+-induced stimulation of Ca2+ uptake was not prevented by 10-5M tetrodotoxin or by replacing sodium with choline in the assay medium. Ca2+ uptake was, however, inhibited by several VSCC antagonists: nitrendipine, D-600, diltiazem and Cd2+. Further, the novel dihydropyridine VSCC agonists, BAY K8644 and CGP 28392, enhanced 50 mM K+-stimulated 45Ca2+ uptake and these effects were blocked by nitrendipine.
Original language | English (US) |
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Pages (from-to) | 2209-2215 |
Number of pages | 7 |
Journal | Life Sciences |
Volume | 36 |
Issue number | 23 |
DOIs | |
State | Published - Jun 10 1985 |
Funding
The authors would like to thank Ellsabeth Cornelison for excellent technical asslstance and Della Akres and Joyce Bonner for preparation of the manuscrlpt. This study was supported by NIH grants DA-02121 and DA-02575 to R.J.M. and a grant from The Mothers' Aid Research Fund of Chlcago Lylng-ln Hospital to G.A.S.
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- Pharmacology, Toxicology and Pharmaceutics(all)