Deleterious effects of nifedipine on smooth muscle cells implies alterations of intracellular calcium signaling

Abstract

Nifedipine (NIF), a calcium channel blocker (CCB) from the first generation of dihydropyridines, induces detrimental effects on patients with cardiovascular diseases. We designed experiments to study, at cellular and molecular level, the mechanisms involved in the induction of deleterious effects by this drug. To this purpose, cultured human smooth muscle cells (HSMC) were used. The effect of NIF and two other CCB (FEL, AML) and inhibitors of intracellular signaling pathways (RR, TG, CAF and GEN) on intracellular calcium [Ca(2+)]I was determined by spectrofluorimetry using Fura 2 AM assay. The results showed that: (i) 10 microM NIF induced the increase of [Ca(2+)]I above the basal values (202.77 +/- 23.98 nM vs. 48.68 +/- 6.45 nM), an effect that was prevented by RR (50.45 +/- 13.9 nM) and was not induced by the two other CCB; (ii) NIF had a thapsigargin-like effect, because it induced the same release of intracellular calcium as TG (212.1 +/- 25.62 nM); (iii) The response to NIF was reduced by 40% after the inhibition of IP3 receptor (121.21 +/- 26.01 nM) and by 50% after the inhibition of tyrosine kinase (101.91 +/- 7.76 nM). Together, these data demonstrate that NIF produces a deregulation of intracellular calcium homeostasis. The abnormal increase of [Ca(2+)]I is due to the activation of store operated channels from the plasma membrane responsible for capacitative calcium entry, a process modulated by the activity of tyrosine kinase and the Ca(2+)-ATPase pump from the sarcoplasmic reticulum.

L-type voltage-dependent Ca2+ channels in cerebral microvascular endothelial cells and ET-1 biosynthesis

“…However, others have reported that nifedipine can increase [Ca 2ϩ ] i by activation of Ca 2ϩ release from intracellular store in smooth muscle cells and extracellular Ca 2ϩ influx in coronary endothelial cells (3,25). The intracellular effects of nifedipine reported may be due to high concentration (10 M) or to the cell type used in the study.…”

“…In the presence of nifedipine, Ca 2ϩ signals in response to bradykinin but not 5-HT application were not completely blocked. This could be due to Ca 2ϩ entry via channels other than voltage-operated and/or effects of nifedipine causing Ca 2ϩ release from an internal store (25). The latter is unlikely because the same was not observed after application of 5-HT.…”

Intracellular Ca2+ stores are essential for injury induced Ca2+ signaling and re‐endothelialization

“…In some of those patients who receive treatments where endothelial lining is compromised, calcium channel blockers are sometimes used, for example to control hypertension (Eisenberg et al, 2004). Some of those blockers, such as amlodipine, nicardipine and nifedipine, have been shown to affect intracellular Ca 2þ stores and [Ca 2þ ] i rise in response to various stimuli (Stepien and Marche, 2000;Raicu and Florea, 2001;Power and Sah, 2005). Our results show that nifedipine and verapamil abolished [Ca 2þ ] i rise in response to mechanical stimulation.…”

Clarification of serotonin‐induced effects in peripheral artery disease observed through the femoral artery response in models of diabetes and vascular occlusion: The role of calcium ions

“…These results indicate that nifedipine was able to affect some intracellular pathways in the absence of endothelial tissues. Although this was not expected at the beginning of our investigation, it is a known fact that nifedipine can alter intracellular calcium signalling pathways . More precisely, serotonin will activate 5HT 2 receptors on the surface of smooth muscle cells .…”

“…Although this was not expected at the beginning of our investigation, it is a known fact that nifedipine can alter intracellular calcium signalling pathways. 25 More precisely, serotonin will activate 5HT 2 receptors on the surface of smooth muscle cells. 9 These receptors are Gq-coupled receptors, and after serotonin coupling, an activation of phospholipase C will be followed with the subsequent release of inositol triphosphate (IP3).…”