Dual effect of dihydropyridines on 45Ca uptake induced by the K+ —channel blocker 4-aminopyridin on mast cells
✍ Scribed by N. Eleno; L. Botana; J. Espinosa
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- English
- Weight
- 527 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
The 1,Qdihydropyridines (DHP) are calcium antagonists and represent a new class of drugs which act by a selective inhibition of Ca++ influx through voltage-operated calcium channels. We report the effect of nifedipine (Bay A 1040), nisoldipine (Bay K 5552) and nitrendipine (Bay E 5009) on the histamine release and on the 45Ca uptake promoted by 4aminopyridin in mast cells. These cells treated with DHP f10-12-10-3 M) activated the secretory response in a dose-dependent manner in the range of concentrations 10-6-10-3 M, whereas concentrations of 10-12-10-6 M did not significantly inhibit the secretion. QAminopyridin, a known K+-channel blocker, induced 45Ca uptake. Pretreatment of mast cells with DHP prior to Qaminopyridin stimulation inhibited or stimulated 45Ca uptake depending on concentration; thus, concentrations of DHP below 10-l2 of nitrendipine and for nisoldipine and nifedipine were inhibitory, while higher doses potentiated 45Ca uptake. These results demonstrate a diversity of pharmacological effects of DHP on mediator secretion and 45Ca uptake in mast cells and throw into question their only properties as Ca++ antagonists.