Haga Y, Dumitrescu A, Zhang Y, Stain-Malmgren R, Sjöquist P O
Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
Pharmacol Toxicol. 1996 Dec;79(6):312-7. doi: 10.1111/j.1600-0773.1996.tb00015.x.
Activated neutrophils are assumed to be one plausible cause of tissue injury in the ischaemic and reperfused myocardium. We studied the inhibitory effects of the calcium antagonists felodipine, nimodipine and verapamil on human neutrophil activation in order to elucidate the mechanisms underlying their myocardioprotective effects and to determine whether calcium antagonists with different chemical structures vary in their effect on neutrophil activation. Neutrophils were stimulated with formyl-Met-Leu-Phe (0.1 microM) or by phorbol myristate acetate (0.16 microM), and the rise in cytosolic calcium and the H2O2 production were determined. For felodipine, the inhibitory effect on granulocyte elastase release was also studied. The calcium antagonists reduced formyl-Met-Leu-Phe and phorbol myristate acetate-induced neutrophil activation in a concentration-dependent manner, the order of potency being: felodipine > nimodipine > verapamil. For felodipine, the IC50 (concentration causing 50% reduction) values were 3 x 10(-6) and 2 x 10(-6) M for the formyl-Met-Leu-Phe-induced cytosolic calcium increase and H2O2 production, respectively. The IC50-value for the phorbol myristate acetate-induced cytosolic calcium increase was 6 x 10(-6) and for H2O2 production 4 x 10(-6) M. For formyl-Met-Leu-Phe-induced granulocyte elastase release, the IC50-value was 5 x 10(-6) M. The inhibitory effect of felodipine on the phorbol myristate acetate-induced granulocyte elastase release did not exceed 50%. Nimodipine was a less potent inhibitor than felodipine for both formyl-Met-Leu-Phe- and phorbol myristate acetate-induced cell activities. Verapamil was even less potent than the other two agents. The present study demonstrates that felodipine potentially suppresses neutrophil activation at micromolar concentrations. However, this observation should not be directly extrapolated to explain the tissue protection by the compounds without evidence of profound local accumulation.
活化的中性粒细胞被认为是缺血再灌注心肌组织损伤的一个可能原因。我们研究了钙拮抗剂非洛地平、尼莫地平和维拉帕米对人中性粒细胞活化的抑制作用，以阐明它们心肌保护作用的潜在机制，并确定具有不同化学结构的钙拮抗剂对中性粒细胞活化的影响是否存在差异。用甲酰 - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸（0.1微摩尔）或佛波酯（0.16微摩尔）刺激中性粒细胞，并测定细胞内钙的升高和过氧化氢的产生。对于非洛地平，还研究了其对粒细胞弹性蛋白酶释放的抑制作用。钙拮抗剂以浓度依赖性方式降低甲酰 - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸和佛波酯诱导的中性粒细胞活化，效力顺序为：非洛地平＞尼莫地平＞维拉帕米。对于非洛地平，甲酰 - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸诱导的细胞内钙增加和过氧化氢产生的IC50（引起50％降低的浓度）值分别为3×10⁻⁶和2×10⁻⁶摩尔/升。佛波酯诱导的细胞内钙增加的IC50值为6×10⁻⁶，过氧化氢产生的IC50值为4×10⁻⁶摩尔/升。对于甲酰 - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸诱导的粒细胞弹性蛋白酶释放，IC50值为5×10⁻⁶摩尔/升。非洛地平对佛波酯诱导的粒细胞弹性蛋白酶释放的抑制作用不超过50％。对于甲酰 - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸和佛波酯诱导的细胞活性，尼莫地平的抑制效力低于非洛地平。维拉帕米的效力甚至低于其他两种药物。本研究表明，非洛地平在微摩尔浓度下可能抑制中性粒细胞活化。然而，在没有证据表明化合物在局部大量蓄积的情况下，这一观察结果不应直接外推用于解释其组织保护作用。
