Calcium uptake studies of 1,4-dihydropyridine agonists into rabbit aortic smooth muscle cells in culture
The effects of the three dihydropyridine calcium channel agonists (/plus minus/)BAY K 8644, (+)202-791 and (/plus minus/)CGP 28392 on /sup 45/Ca/sup + +/ uptake were studied in cultures of rabbit aortic smooth muscle cells. At 10/sup /minus/7/M each agonist enhanced /sup 45/Ca/sup + +/ uptake in 15-50 mM K/sup +/ but had no effect on the basal /sup 45/Ca/sup + +/ uptake at 5 mM K/sup +/. At the uptake threshold of 15 mM K/sup +/ each agonist potentiated /sup 45/Ca/sup + +/ uptake in a dose-dependent manner with half maximal effects at 2.4 nM for (/plus minus/)BAY K 8644, 22 nM for (+)202-791 and 18 nM for (/plus minus/)CGP 28392. The agonists showed no significant antagonistic activity. Responses were antagonized competitively by nifedipine and non-competitively by (/plus minus/)D-600. The /sup 45/Ca/sup + +/ uptake-dose response curves and the half maximal effects of the three agonists were over the same range of concentrations as their inhibition of (/sup 3/H)nitrendipine binding to rat ventricular receptor membrane preparations. The data suggest that these cells mimic the calcium uptake by the intact aorta better than commercial vascular smooth muscle lines or cardiac cells.
- Research Organization:
- G.D. Searle and Company, Skokie, IL (USA)
- OSTI ID:
- 6101764
- Journal Information:
- Life Sci.; (United States), Vol. 44:23
- Country of Publication:
- United States
- Language:
- English
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550201* - Biochemistry- Tracer Techniques