Substance P and Arg-Pro-Lys-Pro-NH-C12-H25-induced mediator release from different mast cell subtypes of rat and guinea-pig

Neurogenic inflammation of Guinea-pig bladder

Capsaicin, substance P, and ovalbumin, instilled into the bladders of naive and ovalbumin (OVA) sensitized guineapigs caused inflammation, as indicated by increased vascular permeability. Histological changes after exposure to these compounds progressed with time from intense vasodilatation to marginalization of granulocytes followed by interstitial migration of leukocytes. In vitro incubation of guinea-pig bladder tissue with substance P and ovalbumin stimulated release of prostaglandin D₂ and leukotrienes. In vitro incubation of bladder tissue with capsaicin, OVA, prostaglandin D₂, leukotriene C₄, histamine, or calcium ionophore A-23587 all stimulated substance P release. These data suggest that bladder inflammation initiated by a variety of stimuli could lead to a cyclic pattern of release of inflammatory mediators and neuropeptides, which could result in amplification and persistence of cystitis after the inciting cause has subsided.

The beta(2)-agonist salbutamol inhibits bronchoconstriction and leukotriene D(4) synthesis after dry gas hyperpnea in the guinea-pig

Isocapnic dry gas hyperpnea-induced bronchoconstriction (HIB) in the guinea-pig is mediated by both tachykinin release from airway sensory nerve C-type fiber terminals and secondary synthesis of cysteinyl-leukotrienes, in particular LTD(4). Beta (beta)(2)-agonists are potent bronchodilators but potentially could also inhibit the airway response to hyperpnea challenge via effects on the release of LTD(4)from airway cells in vivo. The purpose of this study was to test the hypothesis that beta(2)agonists attenuate HIB in guinea-pigs, in part, by reduction in LTD(4)release in vivo. Twenty-six guinea-pigs (400-550 g) were anesthetized with xylazine (7 mg/kg) and pentobarbital (65 mg/kg), tracheotomized and mechanically ventilated with a small animal ventilator using a tidal volume of 3 ml and a breathing frequency of 60 breaths/min. Dry gas (95%O(2)/5%CO(2)) with a 4 ml tidal volume and a breathing frequency of 150/min was used for hyperpnea challenge. Challenge with isocapnic dry gas triggered a significant increase in pulmonary resistance (0.3 +/- 0.02 vs. 0.57 +/- 0.06 cmH(2)O/ml per s; P=0. 017; n=13) and excretion of LTD(4)in the bile (baseline: 2.43 vs. HIB: 4.66 pmol/h; P=0.04). Salbutamol pretreatment completely blocked the airway response to the challenge (0.3+/-0.02 vs. 0.3+/-0. 05 cmH(2)O/ml per s; n=13) and reduced the biliary excretion of LTD(4)(baseline: 2.42 pmol/h; vs. HIB: 2.40 pmol/h). We conclude that salbutamol inhibited the airway responses to dry gas hyperpnea challenge and LTD(4)synthesis by the airway cells.

Mast cells mediate the severity of experimental cystitis in mice

PURPOSE

We hypothesized that experimental cystitis induced by substance P (SP) or E. coli lipopolysaccharide (LPS) would be less severe in mice rendered mast cell deficient by genetic manipulation.

MATERIALS AND METHODS

Two strains of mast-cell deficient mice (WBB6F1- kitW/kitW-v or kitW/kitW-v and WCB6F1-Sl/Sld or Sl/Sld) and their congenic, normal (+/+) counterparts were used. Cystitis was induced in female mice by intravenous injection of SP (0.1 ml.; 10(-6) M) or E. coli LPS (0.1 ml.; 2 mg./ml.), and inflammation was assessed by Evans blue dye extravasation. In a separate group of kitW/kitW-v and congenic normal mice, cystitis was induced by intravesical infusion of SP (0.05 ml.; 10(-5) M) or E. coli LPS (0.05 ml.; 100 microg./ml.) and compared with intravesical pyrogen-free saline (0.05 ml.; 0.9%). Severity of cystitis was determined by histological evaluation of the bladder wall 24 hours after intravesical infusions.

RESULTS

Intravenous SP or LPS stimulated increased plasma extravasation in congenic normal mice but not in mast cell-deficient mice. Intravesical SP or LPS resulted in increased edema, leukocytic infiltration, and hemorrhage within the bladder wall in congenic normal mice, but the only histological evidence of inflammation in the bladders of kitW/kitW-v mice was increased hemorrhage in response to LPS.

CONCLUSIONS

This study indicates that mast cells modulate the inflammatory response of the bladder to SP and LPS in mice. Although clinical trials of the use of antihistamines to treat or prevent cystitis have not been successful, these results suggest that therapies directed toward preventing mast cell activation may yet prove effective in treating cystitis.

Inhibition of substance P-induced histamine release from rat peritoneal mast cells by low doses of protoporphyrin plus long-wave ultraviolet light irradiation: decreased intracellular calcium as a possible mechanism

BACKGROUND

A considerable amount of recent interest has been devoted to the down-regulatory effects of photosensitizers plus long-wave ultraviolet light (UVA) irradiation on multiple biologic systems. However, these effects on mast cells are controversial.

OBJECTIVE

We have investigated the effect of low doses of protoporphyrin (PP) plus UVA irradiation (PP/UVA) on substance P (SP)-induced histamine release from rat mast cells.

METHODS

Rat peritoneal mast cells purified on a Percoll gradient were treated with 3 ng/mL PP and/or UVA, and challenged with SP. In some experiments, IgE-sensitized mast cells were stimulated by antirat IgE in the presence of phosphatidylserine. Histamine released from mast cells and intracellular calcium concentrations ([Ca2+]i) were measured, respectively.

RESULTS

SP at a concentration of 10(-5) mol/L caused a significant histamine release with the increase in [Ca2+]i. PP or UVA irradiation alone at doses used in the present study induced no histamine release from mast cells and had no significant effects on SP-induced histamine release from the cells. On the other hand, PP/UVA inhibited SP-induced histamine release in a dose-dependent manner of UVA with the reduction of SP-induced maximal increases in [Ca2+]i. Comparing with the inhibitory effects of PP/UVA on anti-IgE-induced histamine release from IgE-sensitized mast cells and maximal increases in [Ca2+]i in the cells, the inhibitory effects of PP/UVA on the findings in SP-stimulated mast cells were less.

CONCLUSION

These data suggest that low doses of PP/UVA inhibits histamine release from SP-activated rat peritoneal mast cells through the suppression of [Ca2+]i.

Role of mucosal mast cells in early vascular permeability changes of intestinal DTH reaction in the rat

Previously, it was shown that depletion and stabilization of the mucosal mast cell around the time of challenge were very effective in reducing delayed-type hypersensitivity (DTH) reactions in the small intestine of the rat. The role of mucosal mast cells in the early component of intestinal DTH reaction was further investigated in this study. In vivo small intestinal vascular leakage and serum levels of rat mast cell protease II (RMCP II) were determined within 1 h after intragastric challenge of rats that had been sensitized with dinitrobenzene 5 days before. A separate group of rats was used to study vasopermeability in isolated vascularly perfused small intestine after in vitro challenge. To investigate the effects of mast cell stabilization on the early events of the DTH reaction, doxantrazole was used. The influence of sensory nerves was studied by means of neonatal capsaicin-induced depletion of sensory neuropetides. Within 1 h after challenge, a significant increase in vascular permeability was found in vivo as well as in vitro. This was associated with a DTH-specific increase in RMCP II in the serum, indicating mucosal mast cell activation. In addition, doxantrazole treatment and caspaicin pretreatment resulted in a significant inhibition of the DTH-induced vascular leakage and an increase in serum RMCP II. These findings are consistent with an important role for mucosal mast cells in early vascular leakage changes of intestinal DTH reactions. In addition, sensory nervous control of mucosal mast cell activation early after challenge is demonstrated.

Inhibition of substance-P-induced histamine release from rat peritoneal mast cells by 8-methoxypsoralen plus long-wave ultraviolet light irradiation: decreased intracellular calcium as a possible mechanism

Rat peritoneal mast cells purified on a Percoll gradient were activated by substance P (SP) and the effect of 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet light (UVA) irradiation (8-MOP/UVA) on SP-induced histamine release from the cells was investigated. At a concentration of 10(-5) M SP caused a significant histamine release. 8-MOP or UVA irradiation alone at the doses used in the present study neither induced a histamine release nor had any significant effects on SP-induced histamine release from mast cells. On the other hand, 8-MOP/UVA inhibited SP-induced histamine release; this inhibition was dependent on the UVA doses (0.5-3.0 J/cm2) and was accompanied by a reduction in the rise in intracellular calcium concentrations ([Ca2+]i). These data suggest that 8-MOP/UVA inhibits histamine release from SP-activated rat peritoneal mast cells by suppressing the rise in [Ca2+]i.

The effects of tachykinins on inflammatory and immune cells

The aim of this article is to provide an up-dated overview of the available information on the role played by tachykinins in recruiting/regulating the function of immune/inflammatory cells, an issue which has received considerable input from the recent availability of potent and selective antagonists for tachykinin receptors. It appears that NK1 receptors play a role in mediating the extravascular migration of granulocytes into inflamed tissues in response to various inflammatory stimuli, although this effect may not be due to the expression of NK1 receptors by granulocytes themselves. Several data also imply a role for NK1 and NK2 receptors in regulating immune function. No data are available to suggest the expression of NK3 receptors by inflammatory/immune cells. Mast cell degranulation by substance P appears to be a non-receptor dependent response which may take place in vivo during intense stimulation. An emerging concept in the field relates to the ability of certain immune cell types to synthesize and possibly release tachykinins. Immune cells could represent an additional source of tachykinins in inflamed tissues, providing a non-neurogenic tachykininergic contribution to the local inflammatory process.

Possible mechanisms of the concentration-dependent action of substance P to induce histamine release from rat peritoneal mast cells and the effect of extracellular calcium on mast-cell activation

Rat peritoneal mast cells purified on a Percoll gradient were loaded with the fluorescent Ca2+ indicator fura-2 and were challenged with different concentrations of substance P (SP), and intracellular calcium concentrations ([Ca2+]i) were measured by a spectrofluorometric assay. SP at 5 x 10(-6) mol/l and 10(-5) mol/l caused a significant histamine release with a significant increase in [Ca2+]i in a dose-dependent manner. However, SP at 10(-8)-10(-6) mol/l did not induce either histamine release or increase in [Ca2+]i. Extracellular calcium at 0.9 mM inhibited the histamine release with a significant reduction of [Ca2+]i compared with that of the cells in a nominally calcium-free condition. These results indicate that the action of SP on rat mast cells relies upon [Ca2+]i to induce histamine release.

Histamine release induced by human natriuretic peptide from rat peritoneal mast cells

We have been interested in the effects of some popular peptides on tracheal smooth muscle. Previously, we reported that atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) had dose-dependent relaxant effects on guinea pig tracheal smooth muscle. In this study, we compared the effects of ANP, BNP and CNP on histamine release from rat peritoneal mast cells. ANP and BNP were more potent than CNP, dose-dependently increasing histamine release at a concentration of 10(-7) M or higher. CNP induced histamine release at a concentration of 10(-6) M or higher. Extracellular calcium inhibited the histamine release induced by all 3 peptides. In conclusion, the effects of these 3 peptides in rat peritoneal mast cells demonstrated adverse reactions for respiratory diseases, although our previous results showed that these peptides caused relaxation of guinea pig tracheal smooth muscle. We should note that the drugs have different actions in each organ.

Delayed-type hypersensitivity-induced increase in vascular permeability in the mouse small intestine: inhibition by depletion of sensory neuropeptides and NK1 receptor blockade

1. This study investigates the effects of capsaicin-induced depletion of sensory neuropeptides and of neurokinin1 (NK1) receptor blockade on delayed-type hypersensitivity (DTH)-induced changes of vascular permeability in the small intestine of the mouse. 2. The DTH reaction in the small intestine was elicited by dinitrofluorobenzene (DNFB)-contact sensitization followed by oral dinitrobenzene sulphonic acid (DNBS) challenge. To assess vascular leakage the accumulation of the plasma marker, Evans blue (EB), was measured 2, 24 and 48 h after the challenge. 3. The small intestinal DTH reaction was characterized by a significant increase in vascular permeability 24 h after the challenge of previously sensitized mice when compared to vehicle-sensitized mice (P < 0.05, ANOVA). Capsaicin-induced depletion of sensory neuropeptides, two weeks before the sensitization, completely inhibited the DTH-induced increase in small intestinal vascular permeability at 24 h (P < 0.05, ANOVA). Vehicle/control: 108.2 +/- 8.6 ng EB mg-1 dry weight; vehicle/DTH 207.8 +/- 25.1 ng EB mg-1 dry weight; capsaicin/control: 65.8 +/- 11.9 ng EB mg-1 dry weight; capsaicin/DTH: 84.3 +/- 7.6 ng EB mg-1 dry weight. 4. The tachykinins, substance P and neurokinin A (1.5 to 50 x 10(-11) mol per mouse, i.v.), induced an increase in vascular leakage in the small intestine of naive mice. The specific NK1 receptor antagonist, RP67580 (10(-9) mol per mouse, i.v.) was the most effective in reducing the substance P-induced plasma extravasation when compared with other NK receptor antagonists, FK224 and FK888. 5. Treatment of DNFB-sensitized mice with RP67580 (10-9 mol per mouse, i.v.) immediately before and 1 h after the DNBS challenge resulted in a significant reduction of the DTH-induced increase in vascular permeability at 24 h (vehicle/control: 107.5 +/- 8.8 ng EB mg-1 dry weight; RP67580/control:95.4 +/- 5.4 ng EB mg-1 dry weight; vehicle/DTH: 206.6 +/- 22.6 ng EB mg-1 dry weight; RP67580/DTH:132.6 +/- 13.6 ng EB mg-1 dry weight, P<0.05, ANOVA).6. These results suggest that sensory nerves are involved in the development of small intestinal DTH reactions in the mouse. NK1 receptors could play an important role in the initiation of the DTH-induced changes in vascular leakage.

Calcium influx and protein kinase C alpha activation mediate arachidonic acid mobilization by the human NK-2 receptor expressed in Chinese hamster ovary cells

We have cloned a cDNA encoding the human ileal neurokinin-2 (NK-2) receptor which mediates powerful neurokinin A-stimulated arachidonic acid (AA) and prostaglandin release when expressed in CHO cells. Two major signal transduction events appear to underlie this response. Firstly, AA liberation is critically dependent upon agonist-stimulated influx of extracellular Ca2+ although not release from intracellular stores. Secondly, NK-2 receptor-linked AA mobilization requires concomitant PKC activation and based upon limited subtype immunodetectability as well as toxin, identical pretreatment inhibits AA release partially and blocks PKC alpha translocation completely. These observations indicate that in this cell system AA liberation reflects NK-2 receptor-dependent activation of two distinct but converging signal transduction pathways regulated by different G-protein species and involving Ca2+ influx and PKC alpha activation.

Substance P induces a rise in intracellular calcium concentration in human T lymphocytes in vitro: evidence of a receptor-independent mechanism

The neuropeptide substance P (SP) has been shown to play an important role as a mediator of neurogenic inflammation. Moreover, in vitro SP is capable of modulating the activity of lymphocytes, monocytes and polymorphonuclear cells. We have examined one of the early events that occur after addition of SP to human peripheral blood mononuclear cells (PBMC). Addition of 10(-6)-10(-4) M SP to human peripheral blood mononuclear cells results in a dose-dependent rise in intracellular calcium concentration as determined by FACS analysis. We show that the effect of SP cannot be attenuated by the SP receptor antagonist [D-Pro4,D-Trp7,9]-SP(4-11), indicating that the response is not mediated via a SP receptor. Amphiphilic peptides like SP appear to have the capacity to insert themselves into the cell membrane and interact directly with intracellular proteins. This hypothesis is supported by the fact that the amphiphilic analogue of SP, [D-Pro2,D-Phe7,D-Trp9]-SP, is capable of inducing a calcium response in our system, although it is known as an SP receptor antagonist. Functionally, we show that SP increases the proliferative response of T cells induced by suboptimal concentrations of the mitogen PHA. These data provide evidence of a potential role of SP in the regulation of lymphocyte activation.

Characteristics of deoxycholic acid-induced histamine release from mast cells of guinea-pig rectocolonic mucosa and rat peritoneal cavity

Deoxycholic acid (DA) caused a dose-related release of histamine (HR) from mast cells of rat peritoneum (RPMC) and mucosal cells of guinea pig rectocolon (RCMC). In both cell populations, DA-induced HR was: (1) accompared by a parallel release of lactate dehydrogenase (LDH), (2) not affected by metabolic inhibitors, (3) dependent on time of incubation, temperature and pH, and affected by Ca++ concentration in RPMC but not in RCMC. DA-induced HR from RCMC may be involved in certain functional disorders of the colon.

Effect of picumast on histamine release from rat cardiac and peritoneal mast cells

Compound 48/80-induced histamine release (HR) from the isolated perfused rat heart was markedly and significantly inhibited by picumast (PIC), possibly by acting as a calmodulin antagonist (CMA) or membrane stabilizer. Trifluoperazine (TFP, another CMA in clinical use) had a similar effect. However, an action as CMA being the basis of inhibition of HR could not be confirmed in another 'allergy' model, namely HR from rat peritoneal mast cells (RPMC). PIC, TFP and two other CMA, W7 and N-(4-aminobutyl)-5-chloro-1-naphthalenesulfonamide) failed consistently to inhibit 48/80-induced HR from RPMC, and when used on their own at high concentration these compounds caused HR. PIC and TFP also potentiated the heat-induced haemolysis of rat erythrocytes, i.e. lacked membrane stabilizing effect in this model.