Sigma-1 Receptor Ligands Chlorpromazine and Trifluoperazine Attenuate Ca2+ Responses in Rat Peritoneal Macrophages.

Sigma-1 receptors are ubiquitous multifunctional ligand-regulated molecular chaperones in the endoplasmic reticulum membrane with a unique history, structure, and pharmacological profile. Sigma-1 receptors bind ligands of different chemical structure and pharmacological action and modulate a wide range of cellular processes in health and disease, including Ca2+ signaling. To elucidate the involvement of sigma-1 receptors in the processes of Ca2+ signaling in macrophages we studied the effect of sigma-1 receptor ligands, phenothiazine neuroleptics chlorpromazine and trifluoperazine, on Ca2+ responses induced by inhibitors of endoplasmic Ca2+-ATPases thapsigargin and cyclopiazonic acid, as well as by disulfide-containing immunomodulators Glutoxim and Molixan in rat peritoneal macrophages. Using Fura-2AM microfluorimetry we showed for the first time that chlorpromazine and trifluoperazine inhibit both phases of Ca2+ responses induced by Glutoxim, Molixan, thapsigargin, and cyclopiazonic acid in rat peritoneal macrophages. The data obtained indicate the participation of sigma-1 receptors in a complex signaling cascade caused by Glutoxim or Molixan and leading to an increase in intracellular Ca2+ concentration in macrophages. The results also indicate the involvement of sigma-1 receptors in the regulation of store-dependent Ca2+entry in macrophages.

Neuroleptic Chlorpromazine Modulates Ca2+ Responses in Macrophages.

Using Fura-2AM microfluorimetry, we have shown for the first time that sigma-1 receptor antagonist neuroleptic chlorpromazine significantly inhibits glutoxim- and molixan-induced Ca2+ responses and Ca2+ responses induced by endoplasmic reticulum Са2+-ATPase inhibitors thapsigargin and cyclopiazonic acid in rat peritoneal macrophages. The results suggest the involvement of sigma-1 receptors in the signaling cascade induced by glutoxim or molixan and leading to intracellular Ca2+ concentration increase and in the regulation of store-dependent Ca2+ entry in macrophages.

Sigma-1 Receptor Agonist Amitriptyline Inhibits Store-Dependent Ca2+ Entry in Macrophages.

Using Fura-2AM microfluorimetry, we have shown for the first time that sigma-1 receptor agonist-tricyclic antidepressant amitriptyline-significantly inhibits store-dependent Ca2+ entry, induced by endoplasmic Ca2+-ATPase inhibitors thapsigargin and cyclopiazonic acid, in rat peritoneal macrophages. The results suggest a possible involvement of sigma-1 receptors in the regulation of store-dependent Ca2+ entry in macrophages.

Amitriptyline 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 agonist, tricyclic antidepressant amitriptyline, significantly inhibits glutoxim- and molixan-induced Ca2+-responses in rat peritoneal macrophages. The results suggest possible involvement of sigma-1 receptors in the signaling cascade induced by glutoxim or molixan and leading to intracellular Ca2+ concentration increase in macrophages.

Sigma-1 Receptor Antagonist Haloperidol Attenuates Store-Dependent Ca2+ 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.

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.

The effect of chlorpromazine on intracellular Ca2+ 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-ß-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-ß-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-ß-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.

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.

5-Lipoxygenase inhibitor zileuton inhibits Ca(2+)-responses induced by glutoxim and molixan in macrophages.

Using Fura-2AM microfluorimetry, we have shown for the first time that 5-lipoxygenase specific inhibitor antiasthmatic agent zileuton significantly inhibits Ca(2+)-responses induced by glutoxim and molixan in macrophages. The results support 5-lipoxygenase involvement in the effect of glutoxim and molixan on intracellular Ca(2+) concentration in macrophages and indicate the inadvisability of a combined use of drugs glutoxim and molixan and antiasthmatic agent zileuton.

Methyl-ß-cyclodextrin inhibits Ca2+-responses induced by glutoxim and molixan in macrophages.

Using Fura-2AM microfluorimetry, we have shown for the first time that methyl-ß-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.

[THE EFFECT OF EPOXYGENASE INHIBITORS ON Ca(2+)-RESPONSES INDUCED BY GLUTOXIM AND MOLIXAN IN MACROPHAGES].

Using Fura-2AM microfluorimetry the possible involvement of epoxygenase pathway of arachidonic acid metabolism in the effect of glutoxim and molixan on intracellular Ca2+ concentration in rat peritoneal macrophages was investigated. It was shown for the first time that preincubation of the macrophages with epoxygenase inhibitors, proadifen and econazole, significantly decreases the intracellular Ca2+ concentration increase induced by glutoxim and molixan. The addition of the epoxygenase inhibitors during the already developed store-dependent Ca(2+)-entry induced by glutoxim or molixan partially inhibits Ca(2+)-entry. The obtained data suggest the involvement of the products and/or enzymes of epoxygenase pathway of the arachidonic acid metabolism in the glutoxim and molixan effect on the Ca2+ signaling processes in macrophages.

Involvement of the Arp2/3 complex and WASP proteins in the effect of glutoxim and molixan on intracellular Ca(2+) concentration in macrophages.

The Fura-2AM fluorescent Ca(2+) probe was used to study the possibility that the Arp2/3 complex and WASP proteins are involved in the effects of glutoxim and molixan on the intracellular Ca(2+) concentration in macrophages. It has been demonstrated that preincubation of macrophages with inhibitors of the Arp2/3 complex or WASP proteins (CK-0944666 or wiskostatin, respectively) results in a significant suppression of Ca(2+)-responses induced by glutoxim or molixan. This suggests that polymerization of actin filaments is a process involved in the effect of glutoxim or molixan on intracellular Ca(2+) concentration in macrophages.

Phospholipase A2 inhibitors modulate the effects of glutoxim and molixan on the intracellular Ca(2+) level in macrophages.

Using the fluorescent Ca(2+) 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 Ca(2+) 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 Ca(2+) 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.

[Arp2/3 complex is involved in the effect of glutoxim and molixan on intracellular Ca2+ concentration in macrophages].

The involvement of Arp2/3 complex, which causes actin filament branching, in the effect of drugs glutoxim and molixan was investigated. Using Fura-2AM microfluorimetry it was shown for the first time that Arp2/3 complex inhibitor CK-0944666 almost completely prevents the increase in intracellular Ca2+ concentration, induced by glutoxim or molixan in macrophages. The data suggest the involvement of Arp2/3 complex in the glutoxim and molixan effect on the Ca2+ signalling processes in macrophages.