A. A. Naumova

The effect of chlorpromazine on intracellular Ca 2+ concentration in macrophages

Using Fura-2AM microfluorimetry, it was shown for the first time that neuroleptic chlorpromazine causes intracellular Ca2+ concentration increase in macrophages due to Ca2+ mobilization from intracellular Ca2+ stores and subsequent Ca2+ entry from the external medium. Chlorpromazine-induced Ca2+ entry is inhibited by La3+ and 2-aminoethoxydiphenyl borate and is associated with Ca2+ store depletion.

Methyl-β-cyclodextrin inhibits Ca(2+)-responses induced by glutoxim and molixan in macrophages.

Using Fura-2AM microfluorimetry, we have shown for the first time that methyl-β-cyclodextrin, inducing cholesterol extraction from membranes and raft disruption, significantly inhibits glutoxim- and molixan-induced Ca2+-responses in rat peritoneal macrophages. The results suggest that intact rafts are necessary for signaling cascade induced by glutoxim or molixan and leading to intracellular Ca2+ concentration increase in macrophages.

Phospholipase A2 inhibitors modulate the effects of glutoxim and molixan on the intracellular Ca2+ level in macrophages

Using the fluorescent Ca2+ probe Fura-2AM, the possible involvement of phospholipase A2, the key enzyme in the arachidonic acid cascade, in the effect of drugs glutoxim and molixan on the intracellular Ca2+ concentration in macrophages was studied. It was shown for the first time that preincubation of macrophages with the classical phospholipase A2 inhibitor, 4-bromophenacyl bromide, as well as with glucocorticosteroids prednisolone and dexamethasone significantly inhibits Ca2+ responses induced by glutoxim or molixan in macrophages. These results indicate the involvement of phospholipase A2 and arachidonic acid cascade in glutoximand molixan-induced signaling in macrophages.

Involvement of small G proteins and vesicle traffic in the glutoxim and molixan effects on the intracellular Ca(2+) concentration in macrophages.

252 Glutoxim (bisodium salt of oxidized glutathione (GSSG) containing nanoconcentrations of cissplatii num; PharmaVAM, Russia) is a pharmacological GSSG analogue used as an immunomodulating and hematopoesissstimulating agent in the complex therr apy of bacterial and viral infections, psoriasis, and in radioo and chemotherapy of malignant tumors [1]. Molixan (PharmaVAM) is a complex of glutoxim and inosine with an antiviral, immunomodulating, and hepatoprotective action used in the therapy of acute viral hepatitis B and C, mixed hepatitis, and liver cirr rhosis [1]. Glutoxim and molixan belong to the pharr macological group of thiopoetines, which affect intraa cellular redox regulation. However, the cellular and molecular mechanisms of their action are insuffii ciently understood. In our previous studies, it was first shown that GSSG, glutoxim, and molixan increased the intracell lular Ca 2+ concentration ([Ca 2+ ] i) in rat peritoneal macrophages by mobilizing calcium ions from thapsii garginnsensitive Ca 2+ stores and subsequently stimuu lating the Ca 2+ uptake [2–4]. Using a wide range of agents affecting different components of intracellular signaling systems, we first identified the principal elements of the signal cascade triggered by GSSG and glutoxim and resulting in a [Ca 2+ ] i increase in macrophages, namely, tyrosine kinases and tyrosine phosphatases [3, 5], phosphatii dylinositol kinases [6], and the key enzymes of the phosphoinositide signaling system, phospholipase C and protein kinase C [7]. It was also found that the effects of glutoxim and molixan on [Ca 2+ ] i in macc rophages were mediated by actin cytoskeleton elee ments [8] and microtubules [9]. The involvement of microtubules and the actin cytoskeleton in the glutoxim and molixan action on [Ca 2+ ] i in macrophages invites the assumption that macrophage activation induced by these agents is mediated by vesicle traffic. It is known that intracellu lar trafficking of secretory vesicles depends on microo tubules, which regulate the transport efficiency and organize the vesicle traffic by acting like cellular highh ways. Agents causing microtubule disintegration have been shown to inhibit secretion in different types of cells [10]. In addition, it was reported that glutoxim could induce vesicle exocytosis in macrophages conn taining M. tuberculosis [11]. Based on these data, we considered it worthwhile to investigate the possible involvement of vesicle transport and small G proteins, important components of the exocytosis signaling pathway, in mediating the glutoxim and molixan effects on the [Ca 2+ ] i level in macrophages. Experiments were …

Trifluoperazine Attenuates Store-Dependent Ca2+ Entry in Macrophages

Using Fura-2AM microfluorimetry, we have shown for the first time that preincubation of macrophages with the calsequestrin inhibitor neuroleptic trifluoperazine leads to a significant inhibition of the store-dependent Ca2+ entry induced by endoplasmic Ca2+-ATPase inhibitors thapsigargin or cyclopiazonic acid in rat peritoneal macrophages. The results suggest calsequestrin involvement in the regulation of the store-dependent Ca2+ entry in macrophages.

Sigma-1 Receptor Antagonist Haloperidol Attenuates Store-Dependent Ca 2+ Entry in Macrophages

Using Fura-2AM microfluorimetry, we have shown for the first time that preincubation of macrophages with sigma-1 receptor antagonist haloperidol leads to a significant inhibition of the store-dependent Ca2+ entry induced by endoplasmic Ca2+-ATPase inhibitors thapsigargin or cyclopiazonic acid in rat peritoneal macrophages. The results suggest the involvement of the sigma-1 receptor in the regulation of storedependent Ca2+ entry in macrophages.

Phospholipase A2 Inhibitors Modulate the Effect of Trifluoperazine on the Intracellular Ca2+ Concentration in Macrophages

Using Fura-2AM microfluorimetry, it was shown for the first time that phospholipase A2 inhibitors 4-bromophenacyl bromide and glucocorticosteroids prednisolone and dexamethasone attenuate Ca2+ responses induced by neuroleptic trifluoperazine in macrophages. The results suggest the involvement of phospholipase A2 and arachidonic acid metabolism cascade in the effect of trifluoperazine on intracellular Ca2+ concentration in macrophages.

Inhibitors of the Metabolism of Arachidonic Acid Suppress Ca2+ Responses Induced by Trifluoperazine in Macrophages

The influence of the neuroleptic trifluoperazine on the intracellular concentration of Ca2+ in macrophages of rats was studied using a Fura-2AM fluorescent Ca2+ probe. It was found that trifluoperazine causes a dose-dependent increase in the intracellular Ca2+ concentration associated with Ca2+ mobilization from intracellular Ca2+ stores and subsequent entry of Ca2+ into peritoneal macrophages of rats. It was also shown that inhibitors of phospholipase A2 (4-bromophenacyl bromide, prednisolone, and dexamethasone), cyclooxygenases (aspirin and indomethacin), and lipoxygenases (caffeic acid, zileuton, and baicalein) suppress Ca2+ responses induced by trifluoperazine in macrophages. The data obtained indicate the participation of enzymes and/or products of the cascade of arachidonic acid metabolism in the influence of trifluoperazine on the intracellular concentration of Ca2+ in peritoneal macrophages.

Sigma-1 receptor antagonist haloperidol attenuates Ca2+ responses induced by glutoxim and molixan in macrophages

Using Fura-2AM microfluorimetry, we have shown for the first time that sigma-1 receptor antagonist, antipsychotic haloperidol, significantly inhibits glutoxim- and molixan-induced Ca2+-response in peritoneal macrophages. These results indicate possible involvement of sigma-1 receptors in the signal cascade induced by glutoxim or molixan and leading to intracellular Ca2+ concentration increase in macrophages.

Methyl-β-cyclodextrin modulates thapsigargin-induced store-dependent Ca2+ entry in macrophages

Using Fura-2AM microfluorimetry, we have shown for the first time that preincubation of macrophages with methyl-β-cyclodextrin, inducing cholesterol extraction from membranes and raft disruption, leads to significant inhibition of thapsigargin-induced store-dependent Ca2+ entry in rat peritoneal macrophages. In contrast, macrophage treatment with methyl-β-cyclodextrin after Ca2+ entry mechanisms were activated by store depletion by thapsigargin application leads to potentiation of subsequent store-dependent Ca2+ entry. The results suggest that intact lipid rafts are necessary for the activation but not the maintenance of store-dependent Ca2+ entry in macrophages.