Anti-inflammatory effects of L-type calcium channel blockers

Objective: Calcium ion has an important role in the synthesis and release of chemical mediators during inflammation. The aim of this study was to examine the anti-infiammatory effects of L-type calcium channel blockers on acute and chronic inflammation models in rats and also to examine the effects of nicardipine on capillary vascular permeability in rabbits. Material and Methods: Effects on acute phase of inflammation of verapamil, diltiazem and nicardipine (10 mg/kg doses) were compared with diclofenac sodium (25 mg/kg) in histamine-induced paw edema model. After measuring the right hind paw volumes of rats, drugs were injected intraperitoneally 30 minutes later. Paw edema was induced by 0.1 mL subplantar histamine (0.1%) injection to the same paw. Subsequent paw volumes were measured at 30 minutes intervals. Effects of the drugs on the chronic phase were tested with cotton pellet granuloma method in rats, and effect of nicardipine on capillary vascular permeability was examined with hyaluronidase test in rabbits. Results were compared with control groups. Results: In acute inflammation model, after the histamine injections, maximal paw edema was observed at 30 min. While verapamil and diltiazem did not have an anti-inflammatory effect, nicardipine and diclofenac sodium showed significant anti-inflammatory activities of 63.77% (p= 0.000) and 42.93% (p= 0.002), respectively. While verapamil and diltiazem had similar effects to those of the control group and to each other (p> 0.05), nicardipine had the most potent activity (p< 0.05). Also, nicardipine (3 mg/kg) significantly reduced hyaluronidase-induced capillary permeability (p= 0.000). Calcium channel blockers did not show anti-proliferative effects oi the chronic phase of inflammation, Conclusion: Since nicardipine, a calcium channel blocker significantly inhibited histamine-induced acute inflammation and the dissemination area of hyaluronidase, its anti-inflammatory effect may be due to its higher vaso-selectivity on peripheral vascular smooth muscles and on preventing the increase of vascular permeability. Copyright © 2007 by Türkiye Klinikleri