I. Ferjan

Signaling pathway in nerve growth factor induced histamine release from rat mast cells

Abstract.Objective and Design: We investigated a signal transduction pathway involved in NGF induced histamine secretion from mast cells. We compared this mechanism with the exocytosis induced by basic secretagogue compound 48/80.Materials and Methods: Isolated rat peritoneal mast cells were obtained from male Wistar rats. Histamine release was assayed spectrofl uorometrically.Results: We found that tyrosine kinase inhibitor genistein, phospholipase C (PLC) inhibitor U-73122, phosphatidylinositol 3-kinase (PI-3 kinase) inhibitor wortmannin, protein kinase C (PKC) inhibitors, staurosporine and GF109203X, but not MAP kinase inhibitors, SB203580 and PD98059, reduce histamine secretion in NGF provoked mast cell degranulation. In compound 48/80 mediated degranulation, we confi rmed only the involvement of tyrosine kinase and PLC, but not PI-3 kinase, PKC and MAP kinases.Conclusions: Our results indicate that release of histamine from mast cells after stimulation with NGF is regulated by tyrosine kinase, PLC, PI-3 kinase and PKC, but not by MAP kinases. This biochemical pathway differs from that provoked by compound 48/80.

Changes in histamine and serotonin secretion from rat peritoneal mast cells caused by antidepressants

Psychotropic agents modify the release of histamine and serotonin from rat peritoneal mast cells induced by compound 48/80. Some antidepressants, such as clomipramine and fluoxetine (10−8−10−5 mol/l), increase the percentage of released serotonin in the incubation medium but have no effect on histamine release. In contrast, amitriptyline (10−4 mol/l) inhibits the secretion of histamine and permits that of serotonin. The varying effects of antidepressants on the secretion of histamine and serotonin could be explained either by a differential mechanism of secretion of both amines from mast cells or by a selective effect of drugs on the reuptake of serotonin into mast cells after stimulation by compound 48/80. These hypotheses were further investigated in our present study on rat peritoneal mast cells.Our findings suggest that antidepressants influence the secretion and the reuptake process of amines used. Their effects depend on the concentration of the drug. At lower concentrations, antidepressants (amitriptyline, doxepine and clomipramine) produce no effect on the secretion of the amines whereas at higher concentrations (>10−5 mol/l), they inhibit the release. Additionally, mast cells are capable of removing released serotonin from the incubation medium. Serotonin uptake is an active process which increases with the time of incubation with exogenous serotonin and depends on the presence of extracellular Ca2+ and on the temperature of the medium. Preincubation of mast cells with antidepressants inhibits the reuptake of serotonin into mast cells and thus increases the concentration of serotonin in the incubation medium. Since the reuptake of serotonin is a relatively slow process, the elevation of serotonin in the medium is evident only after longer times of incubation.

Chronic pain treatment: the influence of tricyclic antidepressants on serotonin release and uptake in mast cells.

The involvement of serotonin (5-HT) in chronic pain mechanisms is established. 5-HT inhibits central painful stimuli, but recent data suggests that 5-HT could also enhance pain stimulus from the periphery, where mast cells play an important role. We aimed in our study to clarify the influence of selected tricyclic antidepressants (TCAs) on mast cell function: secretion, uptake, and reuptake of 5-HT, that could interfere with 5-HT levels and in this way contribute to the generation of pain. As an experimental model, we used isolated rat peritoneal mast cells and incubated them with selected TCAs (clomipramine, amitriptyline, doxepin, and imipramine) under different experimental conditions. 5-HT release, uptake, and reuptake were determined spectrofluorometrically. We showed that TCAs were able to inhibit 5-HT secretion from mast cells, as well as uptake of exogenous 5-HT and reuptake of secreted 5-HT back into mast cells. The effects of TCAs were concentration dependent; higher concentrations of TCAs inhibited the secretion of 5-HT induced by compound 48/80, whereas lower concentrations of TCAs inhibited 5-HT uptake. The most effective TCA was halogenated clomipramine. As TCAs are well introduced in chronic pain treatment, the insight into mechanisms of action is important for an understanding of their effect in various pain conditions.

Changes in histamine secretion from mast cells caused by digitalis glycosides

Cardiotonic glycosides modify histamine secretion from rat mast cells in the following way. (1) Preincubation (30 min) of mast cells with liposoluble glycosides (10−4 mol/l) increases the spontaneous histamine secretion by about 5%. (2) Preincubation of mast cells with 10−4 mol/l liposoluble glycosides (digitoxine, digoxine, digitoxigenine) decreases histamine release induced by compound 48/80 in the presence of calcium, whereas the water soluble glycoside, strophanthin G, has no effect on the secretion. (3) Preincubation of mast cells in a calcium-free medium with the glycosides (10−4 mol/l) has a dual-effect on histamine secretion induced by compound 48/80: water soluble glycosides (strophanthin G and K) potentiate histamine release, whereas the liposoluble glycosides (digitoxine, digitoxigenine) decrease the secretory response. The difference in the activity of different glycosides could be explained by their dual effects, namely an inhibition of Na+ K+-ATPase which leads to an increase in histamine release, and intracellular action(s) of liposoluble glycosides leading to a decrease of histamine secretion.

Characteristics of the inhibitory effect of tricyclic antidepressants on histamine release from rat peritoneal mast cells.

Antidepressants have been reported to produce different effects on the secretion of histamine from rat peritoneal mast cells. In Ca2+ -containing medium, preincubation of mast cells with amitriptyline inhibits histamine release [1], whereas some other antidepressants (clomipramine, fluoxetine) have no inhibitory effect on the secretion [2, 3]. Our previous results show that the inhibitory effect of some tricyclic antidepressants is greater in the absence of extracellular Ca2+ ions than in the medium containing physiological concentrations of Ca2+ ions. Since many psychotropic agents are able to bind selectively to the intracellular Ca2+ -binding protein calmodulin [4], the inhibitory effect of tricyclic antidepressants could be due to their competition with Ca2+ ions for Ca2+ -binding sites on calmodulin [1] or on the surface of the mast cell membrane. In our present study, we compared the effect of some tricyclic antidepressants (amitriptyline, imipramine, clomipramine, desipramine) on histamine secretion induced by compound 48/80 in a Ca2+ -free medium. The side chain of antidepressants can be linked to the tricyclic structure ofthe drug with a double (C=C) or a single bond (N-C). The presence of a double bond can lead to a restriction on the number of possible conformations that can interact with binding sites on mast cells. Therefore, the structureactivity relations of some antidepressants (amitriptyline and imipramine) were investigated. Additionally, the effect of polarity of some drugs was studied. The polarity of antidepressants used in our experiments increases in the following way: clomipramine < imipramine < desipramine.

Regulatory role of extracellular Na+ and Ca2+ ions in nerve growth factor induced histamine secretion from rat mast cells.

Abstract:Objective and design: This study was aimed to investigate effects of extracellular Na+ and Ca2+ ions on nerve growth factor (NGF) induced histamine release from mast cells.¶Material: Isolated peritoneal mast cells were obtained from male Wistar rats.¶Methods: Cells were suspended in solution with different concentration of Na+ and Ca2+ ions and stimulated with NGF. Histamine release was assayed spectrofluorometrically.¶Results: NGF (0.001–1 μg/ml) dose-dependently releases histamine from mast cell at physiological extracellular Na+ (134 mM) and Ca2+ (1mM) conditions. Lowering extracellular Ca2+ ions to 0.1 mM reduced histamine response to nearly basal level. However, the removal of extracellular Na+ions significantly enhanced the secretion provoked by NGF (0.6 μg/ml) in low Ca2+ medium. Amiloride, an inhibitor of Na+/Ca2+ and Na+/H+ exchangers inhibited the potentiating effect of sodium free conditions.¶Conclusions: Our results suggest that the activity of Na+/Ca2+ and/or Na+/H+ exchange mechanisms could be of particular importance in the secretory process of mast cells induced by NGF.

Comparison of histamine and serotonin release from rat peritoneal mast cells induced by nerve growth factor and compound 48/80.

Nerve growth factor (NGF) is a polypeptide essential for the development and function of neurones in the CNS and PNS. It elicits several biological effects on neuronal and nonneuronal tissues [1]. More recently NGF has been shown to induce histamine release from rat peritoneal mast cells by interacting with the specific membrane NGF receptor [2]. Our previous studies showed that histamine and serotonin release induced by compound 48/80 were mediated by the interaction with a mast cell membrane binding site for basic secretagogues [3]. Since histamine release induced by compound 48/80 is more pronounced than serotonin release, it has been suggested that mast cells may release histamine and serotonin to different extents [4]. After secretion, mast cells are capable of taking up serotonin. The uptake occurs at the same concentration as the release [5, 6], whereas histamine is taken up at higher concentrations. Therefore, the apparent difference between the amine secretion may be also due to differential reuptake of the amines after the secretion. On the basis of differences between the secretion of the amines, it was of interest to compare the release of both amines induced by two secretagogues (NGF and compound 48/80), having different mechanisms of action.

The effect of some anti-inflammatory drugs on histamine and serotonin release from rat peritoneal mast cells

A number of anti-inflammatory drugs, used in the treatment of inflammation and pain due to their inhibitory effect on prostaglandin synthesis, also display non-specific effects on various cells. Rat peritoneal mast cells are an important source of biogenic amines and other inflammatory mediators. Non-steroidal anti-inflammatory drugs have been reported to inhibit, potentiate or have no effect on histamine release [1]. However, there are no equivalent data reporting the effects of these compounds on serotonin release, which we have previously shown to be secreted in different proportions to histamine [2]. In this study, we therefore investigated the effects of some acidic non-steroidal anti-inflammatory drugs (acetylsalicylic acid, diclofenac, indomethacin) and a structurally unrelated drug (auranofin) on the secretion of both amines from rat peritoneal mast cells.

Regulation of nerve growth factor induced histamine and arachidonic acid release from rat mast cells by cannabinoids.

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Imipramine inhibits histamine and serotonin secretion induced by various secretagogues

Tricyclic antidepressants have been reported to reduce inflammation by inhibiting the formation or release of inflammatory mediators [1]. Theoharides et al. reported that amitriptyline inhibited histamine and serotonin release induced by compound 48/80 from rat mast cells [2]. Our previous results also showed that many tricyclic antidepressants have an inhibitory effect on histamine and serotonin secretion induced by compound 48/80 [3, 4]. The inhibition was more pronounced in Ca-free medium [4], suggesting that Ca may play a role in this inhibitory action of the tricyclic antidepressants. In this study, we further investigated the action of the antidepressant drug imipramine on the secretion of histamine and serotonin from rat isolated peritoneal mast cells. The mast cells were activated with various secretagogues, utilizing either extracellular Ca ions (concanavalin A, ionophore A23187) or Ca ions from intracellular stores (compound 48/80).