AbstractThe 1,4‐dihydropyridines (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) ad nitrendipine (Bay E 5009) on the histamine release and on the45Ca uptake promoted by 4‐aminopyridin in mast cells. These cells treated with DHP (10−12−10−3M) activated the secretory response in a dose‐dependent manner in the range of concentrations 10−6−10−3M did not significantly inhibit the secretion. 4‐Aminopridin, a known K+‐channel blocker, induced45Ca uptake. Pretreatment of mast cells with DHP prior to 4‐aminopyridin stimulation inhibited or stimulated45Ca uptake depending on concentration; thus, concentrations of DHP below 10−12of nitrendipine and 10−9for nisoldipine and nifedipine were inhibitory, while higher doses potentiated45Ca uptake. These results demonstrate a diversity of pharmacological effects of DHP on mediator secretion and45Ca uptake in mast cells and throw into question their only
展开▼
