Nifedipine impairs neutrophil respiratory burst by a mechanism other than calcium channel blockade.
Superoxide production by mice neutrophils was inhibited by nifedipine exposure in a dose dependent manner. The inhibition of Ca2+ uptake elicited by nifedipine did not appear to account for the observed effect as the extracellular Ca2+ enrichment and depletion did not produce a significant reversal of the inhibition. Cytosolic free Ca2+ as measured by Quin 2AM fluorescence did not show any significant change, indicating that the effect was independent of the inhibition of Ca2+ influx. In addition nifedipine caused a significant inhibition (p less than 0.01) in NADPH oxidase activity. Our data indicates that nifedipine inhibits superoxide production independent of inhibiting Ca2+ inflow and supports the hypothesis that Ca2+ antagonists affect cellular functions by non Ca2+ mediated process as well.
Nalini
K
K
Department of Cardiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Andrabi
K I
KI
Ganguly
N K
NK
Wahi
P L
PL
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D008165:Luminol / Q000378:metabolism; D008297:Male; D051379:Mice; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology*; D010100:Oxygen / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
D002121:Calcium Channel Blockers; D003574:Cytochrome c Group; D013481:Superoxides; D008165:Luminol; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D009543:Nifedipine; D010100:Oxygen; D002118:Calcium