Sigma-1 Receptor Ligands Chlorpromazine and Trifluoperazine Attenuate Ca 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 Ca signaling. To elucidate the involvement of sigma-1 receptors in the processes of Ca signaling in macrophages we studied the effect of sigma-1 receptor ligands, phenothiazine neuroleptics chlorpromazine and trifluoperazine, on Ca responses induced by inhibitors of endoplasmic Ca-ATPases thapsigargin and cyclopiazonic acid, as well as by disulfide-containing immunomodulators Glutoxim and Molixan in rat peritoneal macrophages.

Neuroleptic Chlorpromazine Modulates Ca 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 Ca responses and Ca responses induced by endoplasmic reticulum Са-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 Ca concentration increase and in the regulation of store-dependent Ca entry in macrophages.

Sigma-1 Receptor Agonist Amitriptyline Inhibits Store-Dependent Ca 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 Ca entry, induced by endoplasmic Ca-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 Ca entry in macrophages.

Sigma-1 Receptor Antagonists Haloperidol and Chlorpromazine Modulate the Effect of Glutoxim on Na Transport in Frog Skin.

Using voltage-clamp technique, the involvement of sigma-1 receptors in the regulation of Na transport in frog skin by the immunomodulatory drug glutoxim was investigated. We have shown for the first time that preincubation of the frog skin with the sigma-1 receptor antagonists haloperidol and chlorpromazine attenuates the stimulatory effect of glutoxim on the Na transport. The results suggest the possible involvement of the sigma-1 receptors in the regulation of Na transport in frog skin epithelium by glutoxim.

Amitriptyline Attenuates Ca 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 Ca-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 Ca concentration increase in macrophages.

Sigma-1 Receptor Antagonist Haloperidol Attenuates Store-Dependent Ca 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 Ca entry induced by endoplasmic Ca-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 Ca entry in macrophages.

Epoxygenase Inhibitors Attenuate the Stimulatory Effect of Glutoxim on Na Transport in Frog Skin.

Using voltage-clamp technique, the involvement of epoxygenases in immunomodulatory drug glutoxim regulation of Na transport in frog skin was investigated. We have shown for the first time that preincubation of the frog skin with epoxygenase inhibitors econazole or proadifen almost completely inhibits the stimulatory effect of glutoxim on Na transport. The data suggest the involvement of the enzymes and/or products of epoxygenase oxidation pathway of arachidonic acid metabolism in glutoxim effect on Na transport in frog skin epithelium.

Trifluoperazine Attenuates Store-Dependent Ca 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 Ca entry induced by endoplasmic Ca-ATPase inhibitors thapsigargin or cyclopiazonic acid in rat peritoneal macrophages. The results suggest calsequestrin involvement in the regulation of the store-dependent Ca entry in macrophages.

Phospholipase A Inhibitors Modulate the Effect of Trifluoperazine on the Intracellular Ca Concentration in Macrophages.

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

The primary cause of muscle disfunction associated with substitutions E240K and R244G in tropomyosin is aberrant behavior of tropomyosin and response of actin and myosin during ATPase cycle.

Using the polarized photometry technique we have studied the effects of two amino acid replacements, E240K and R244G, in tropomyosin (Tpm1.1) on the position of Tpm1.1 on troponin-free actin filaments and the spatial arrangement of actin monomers and myosin heads at various mimicked stages of the ATPase cycle in the ghost muscle fibres.

The effect of chlorpromazine on intracellular Ca concentration in macrophages.

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

Lipoxygenases modulate the effect of glutoxim on Na transport in the frog skin epithelium.

Using voltage-clamp technique, the involvement of lipoxygenases in the effect of immunomodulatory drug glutoxim on Na transport in frog skin was investigated. It was shown for the first time that preincubation of the skin with lipoxygenase inhibitors caffeic acid, baicalein, and nordihydroguaiaretic acid significantly decreases the stimulatory effect of glutoxim on Na transport. The data suggest the involvement of lipoxygenase oxidation pathway of arachidonic acid metabolism in the glutoxim effect on Na transport in frog skin epithelium.

Methyl-β-cyclodextrin modulates thapsigargin-induced store-dependent Ca 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 Ca entry in rat peritoneal macrophages. In contrast, macrophage treatment with methyl-β-cyclodextrin after Ca entry mechanisms were activated by store depletion by thapsigargin application leads to potentiation of subsequent store-dependent Ca entry. The results suggest that intact lipid rafts are necessary for the activation but not the maintenance of store-dependent Ca entry in macrophages.

Sigma-1 receptor antagonist haloperidol attenuates Ca 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 Ca-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 Ca concentration increase in macrophages.

Methyl-β-cyclodextrin inhibits Ca-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 Ca-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 Ca 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.

The inhibitors of Arp2/3 complex and WASP proteins modulate the effect of glutoxim on Na(+) transport in frog skin.

Using voltage-clamp technique, the involvement of WASP proteins and Arp2/3 complex in the effect of immunomodulator drug glutoxim on Na(+) transport in frog skin was investigated. It was shown for the first time that preincubation of the skin with the N-WASP inhibitor wiskostatin or the Arp2/3 complex inhibitor CK-0944666 significantly decreases the stimulatory effect of glutoxim on Na(+) transport. The data suggest the involvement of actin filament polymerization and branching in the glutoxim effect on Na(+) transport in frog skin.

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.

[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.

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.