IgE reactivity and cross-reactivity of Japanese monkeys (Macaca fuscata) to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens

BACKGROUND

The natural occurrence of Japanese cedar (Cryptomeria japonica, CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata). However, the reactivity to Japanese cypress (Chamaecyparis obtusa, CO) pollen allergens in these monkeys has not yet been reported.

OBJECTIVES

The present study was designed to investigate the reactivity to CO pollen allergens in monkeys sensitized to CJ pollen allergens.

METHODS

Serum samples from 40 monkeys naturally sensitized to CJ pollen allergens were collected from four troops. We measured the specific IgE to CO pollen allergens and examined the reactivity to the allergens by intradermal test. Cross-reactivity between CJ and CO pollen allergens was examined by ELISA inhibition method. Furthermore, we examined the sensitivity to the allergens by histamine release assay from leucocytes.

RESULTS

All 40 monkeys had specific IgE to crude and purified major allergens (Cha o 1) of CO pollen. The monkeys showed a positive reaction to CO pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in CJ pollen) was also observed. Specific histamine release to both the major allergens was noted in two monkeys with CJ pollinosis.

CONCLUSION

Japanese monkeys sensitized to Japanese cedar pollen allergens also demonstrate reactivity to Japanese cypress pollen allergens.

Potentiation and suppression of the histamine response by raising and lowering the temperature in canine visceral polymodal receptors in vitro

It is well known that itch and inflammatory pain are enhanced when tissue is warmed, while they are suppressed when tissue is cooled. To see whether these changed sensations are based on the changed response of sensory receptors, the temperature dependency of the excitation of polymodal receptors induced by histamine, which plays an important role both in itch and inflammatory pain, was studied. Single nerve activities of polymodal receptors were recorded from canine testis-spermatic nerve preparations in vitro. Raising the temperature from 34 to 40 degrees C, a temperature below the threshold for the heat response of polymodal receptors, facilitated the histamine-induced nerve discharge to 268% of that at 34 degrees C, while lowering the temperature to 28 degrees C decreased it to 25%. Facilitation of the histamine response was also observed in the noxious temperature range (48 and 51 degrees C). These results suggest that the potentiation of the histamine-induced sensation by increasing the tissue temperature, as well as its suppression by lowering tissue temperature, can be explained by a temperature-dependent response of peripheral sensory receptors to histamine. However, the suppression of itch by noxious heat reported by Bickford (Bickford, R.G., Experiments relating to the itch sensation, its peripheral mechanism, and central pathways, Clin. Sci. Incorp. Heart, 3 (1937) 377-386) cannot be explained by the noxious heat-induced facilitation of the peripheral receptor response reported in this paper.

Granulocyte-macrophage colony-stimulating factor and interleukin-3 cause basophil histamine release by a common pathway: downregulation by sodium

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) are recognized as enhancers, but not as inducers, of histamine release from normal human basophils. However, when extracellular Na+ is removed IL-3 acquires the capacity to induce histamine release. The aim of this study was to evaluate whether GM-CSF can induce basophil histamine release using the same pathway of IL-3. Leucocyte suspensions from normal human subjects were stimulated with GM-CSF, IL-3 and anti-IgE, and histamine release was evaluated by an automated fluorometric method. In a physiological medium, GM-CSF (10 ng/ml) and IL-3 (10 ng/ml) did not provoke histamine release, in spite of an efficient response to anti-IgE (10 micrograms/ml). However, when extracellular Na+ was substituted iso-osmotically with N-methyl-d-glucamine+ or with choline+, GM-CSF and IL-3 were able to trigger histamine release from either mixed leucocyte suspensions or purified human basophils. The effect of GM-CSF on basophil histamine release was dose dependent, with optimal release at a dose of 1 ng/ml after incubation at 37 degrees for 60-120 min. The kinetics of IL-3-induced histamine release were similar, whereas anti-IgE-induced histamine release was more rapid, being almost maximal after incubation for 30 min. A good correlation was found between GM-CSF-induced and IL-3-induced histamine release; furthermore, the combined effects of the two cytokines were less than additive, suggesting that they share the same pathways leading to histamine release. When extracellular Na+ concentration was increased from 0 to 140 mm, histamine release induced by GM-CSF, IL-3 and anti-IgE was reduced progressively. In contrast, histamine release induced by these stimuli was upregulated when the concentration of extracellular Ca2+ was increased. These results provide indirect evidence that GM-CSF and IL-3 can induce basophil histamine release by a common pathway that is downregulated by Na+.

Mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues

Sections of the lower trachea of cattle, fixed in either Carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin O to study the mast cell population. After toluidine blue staining, about twice as many cells in tissue fixed in Carnoy's contained dark blue granules compared with tissue fixed in formalin. In addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin O. Most of these red granules were formalin sensitive. An enzymatic dispersal technique for mast cells is described that yielded 9.4+/-0.4% mast cells (percentage of nucleated cells) with a viability of 92.3+/-0.6%. Spontaneous histamine release was 3.3+/-0.8%. Dispersed mast cells were challenged with various immunological and nonimmunological secretagogues. The calcium ionophores, A23187, ionomyocin, and BrX537A, were effective in releasing up to 94% of histamine in mast cells in a dose-response relationship. Pasteurella haemolytica culture supernate caused about 10% histamine release at a dose of 0.5 mg/mL after correction for spontaneous release. The average histamine content of the mast cells was 6.6+/-1.0 pg/cell. Cytospins of dispersed cells fixed in Carnoy's and stained with alcian blue and safranin O contained mast cells with blue and red granules, and a few cells with a mixture of both granule types. Based on the effects of type of fixation, staining characteristics and histamine content, a mix of subtypes of mast cells is present in the bovine trachea. However, functionally they respond to secretagogues differently than rodent mast cells. Without an immunological secretagogue, studies to determine compounds that will be effective in blocking mast cell degranulation will be limited.

Differential effect of ebselen on compound 48/80- and anti-IgE-induced histamine release from rat peritoneal mast cells

2-Phenyl-1, 2-benzisoselenazol-3-(2H)one (ebselen), a nontoxic seleno-organic compound, exhibits anti-inflammatory activity through the inhibition of many enzymes involved in inflammation. In view of the role played by histamine in the pathophysiology of inflammation, we looked at the effect of ebselen on histamine secretion by rat peritoneal mast cells. It inhibited compound 48/80-induced histamine release in a concentration-dependent manner. Half-maximal and maximal (100%) inhibitory response occurred at 5.10(-7)M and 10(-5)M, respectively. In contrast, ebselen was without any effect on histamine release induced immunologically. Prevention of the inhibitory effect of ebselen by GSH suggests that it interacts with critical thiols involved in the compound 48/80 activation pathway.

Mechanism of peptide-induced mast cell degranulation. Translocation and patch-clamp studies

Substance P and other polycationic peptides are thought to stimulate mast cell degranulation via direct activation of G proteins. We investigated the ability of extracellularly applied substance P to translocate into mast cells and the ability of intracellularly applied substance P to stimulate degranulation. In addition, we studied by reverse transcription--PCR whether substance P-specific receptors are present in the mast cell membrane. To study translocation, a biologically active and enzymatically stable fluorescent analogue of substance P was synthesized. A rapid, substance P receptor- and energy-independent uptake of this peptide into pertussis toxin-treated and -untreated mast cells was demonstrated using confocal laser scanning microscopy. The peptide was shown to localize preferentially on or inside the mast cell granules using electron microscopic autoradiography with 125I-labeled all-D substance P and 3H-labeled substance P. Cell membrane capacitance measurements using the patch-clamp technique demonstrated that intracellularly applied substance P induced calcium transients and activated mast cell exocytosis with a time delay that depended on peptide concentration (delay of 100-500 s at concentrations of substance P from 50 to 5 microM). Degranulation in response to intracellularly applied substance P was inhibited by GDPbetaS and pertussis toxin, suggesting that substance P acts via G protein activation. These results support the recently proposed model of a receptor-independent mechanism of peptide-induced mast cell degranulation, which assumes a direct interaction of peptides with G protein alpha subunits subsequent to their translocation across the plasma membrane.

Strain differences in histamine release from peritoneal mast cells in rats

1. Peritoneal mast cells from Brown-Norway (BN) rats were compared with those from Wistar and Sprague-Dawley (SD) rats. 2. Peritoneal mast cells from BN rats showed the smallest values in number, cell diameter and histamine contents compared with those from Wistar and SD rats. 3. BN rat peritoneal mast cells were more sensitive to compound 48/80 and anti-IgE than were those from Wistar and SD rats, and they showed a higher response to A23187 than did cells from Wistar rats. 4. The histamine release from passively sensitized peritoneal mast cells was weaker in BN rats than was that from Wistar and SD rats.

Nerve-induced histamine release is of little importance in psoriatic skin

Psoriatic plaques contain an increased number of mast cells. Both the histamine concentration and release are increased in lesional skin but the underlying mechanisms are unclear. One hypothesis is that neuropeptides transmitted from thin sensory cutaneous nerves continuously stimulate mast cell release of histamine. The aim of this study was to test this hypothesis by examining if topical anaesthesia of these nerves inhibits histamine release in psoriatic skin. The concentration of histamine was measured in microdialysates obtained from lesional and non-lesional skin before and during topical anaesthesia. Concomitantly skin blood flow was measured with scanning laser Doppler (perfusion) and/or 133Xe clearance (flow) techniques in the microdialysis area. The histamine concentrations (mean +/- SEM) were 34 +/- 4 (n = 21), 14 +/- 1.5 (n = 18) (P < 0. 001) and 2.8 +/- 1 nmol/L (n = 10) in lesional and non-lesional skin and plasma, respectively. After anaesthesia of the microdialysis areas the histamine concentration in psoriatic skin increased to 44 +/- 4 nmol/L (n = 19, P < 0.05), but remained unaltered in uninvolved skin. In anaesthetized lesional skin the perfusion decreased from 3.7 +/- 0.2 to 2.5 +/- 0.3 V and blood flow decreased from 14 +/- 5 to 9 +/- 1 mL/min per 100 g (P < 0.001, n = 10). The calculated release of dermal histamine in involved skin (198 +/- 30 pmol/min per 100 g, n = 10) remained unchanged after local anaesthesia. The results indicate that neurogenic activation of mast cells is of minor importance for continuous histamine release in psoriatic skin and that the vasodilatation in the psoriatic plaque is not mediated by histamine.

[Cisatracurium in patients with compromised kidney function. Pharmacodynamic and intubation conditions under isoflurane-nitrous oxide anesthesia]

OBJECTIVES

The choice of cisatracurium, especially for patients with organ dysfunction, seems to be beneficial, because of organ-independent Hofmann-elimination and less histamine release propensity. This study was designed to investigate pharmacodynamics and intubating conditions after bolus administration of 0.15 mg/kg cisatracurium (3 x ED95) in patients with renal failure and maintained with isoflurane/N2O in oxygen.

METHODS

20 patients with renal failure and 19 patients with normal renal function were studied. Anaesthesia was induced with fentanyl (2-3 micrograms/kg) and thiophentone (4-7 mg/kg). After rapid bolus administration of 0.15 mg/kg cisatracurium (3 x ED95), onset time and intubating conditions were assessed. Clinical duration (DUR 25%), recovery index and duration 90% were investigated by acceleromyography. Changes of mean arterial blood pressure and/or heart rate > or = 20% were defined as clinically significant.

RESULTS

The onset time (3.1 +/- 0.8 min) was shorter in patients without renal failure (Cis-1) than in patients with normal renal function (3.6 +/- 0.8 min), but without statistical significance. Intubating conditions, scored according to a 3-step scale, were slightly better in patients with normal renal function. Other pharmacodynamic parameters did not differ significantly. However, a small tendency to a prolonged recovery with a wide inter-individual variety was characteristic for patients with renal failure. Regarding the hemodynamic actions, only minor individual cardiovascular changes occured. No clinical evidence of histamine release was observed in any patient.

CONCLUSIONS

The result of this clinical study suggest, that cisatracurium is a suitable choice for patients with renal failure. The necessity for an intraoperative neuromuscular monitoring is given by the marked heterogeneity in the recovery parameters in patients with renal failure.

Inhibitory effect of pulmonary surfactant proteins A and D on allergen-induced lymphocyte proliferation and histamine release in children with asthma

The role of pulmonary surfactant proteins in the pathogenesis of airway inflammation and the impact on asthma has not been elucidated. This study was designed to examine the effect of surfactant proteins A (SP-A) and D (SP-D) on phytohemagglutinin- (PHA) and mite allergen Dermatophagoides pteronyssinus (Der p)-induced histamine release and the proliferation of peripheral blood mononuclear cells (PBMC) in children with asthma in stable condition (n = 21), asthmatic children during acute attacks (n = 9), and age-matched control subjects (n = 7). The results show that SP-A and SP-D were able to reduce the incorporation of [3H]thymidine into PBMC in a dose-dependent manner. In addition to the intact, native SP-A and SP-D proteins, a recombinant peptide composed of the neck and carbohydrate recognition domain (CRD) of SP-D [SP-D(N/CRD)] was also found to have the same suppressive effect on lymphocyte proliferation. This effect was abolished by the presence of 100 mM mannose (for SP-A) or maltose (for SP-D) in the culture medium, which suggested that the CRD regions of SP-A and SP-D may interact with the carbohydrate structures on the surface molecules of lymphocytes. The inhibitory effects of surfactant proteins on PHA- and Der p-stimulated lymphocyte responses were observed in stable asthmatic children and age-matched control subjects, while only a mild suppression (< 25%) was seen in activated lymphocytes derived from asthmatic children with acute attacks. SP-A and SP-D were also found to inhibit allergen-induced histamine release, in a dose-dependent manner, in the diluted whole blood of asthmatic children. We conclude that both SP-A and SP-D can inhibit histamine release in the early phase of allergen provocation and suppress lymphocyte proliferation in the late phase of bronchial inflammation, the two essential steps in the development of asthmatic symptoms. It appears that SP-A and SP-D may be protective against the pathogenesis of asthma.

[Biological activity of subretinal fluid in selected in vitro tests]

PURPOSE

The aim of this study was to evaluate the ability of SRF to activate autologous leucocytes derived from the peripheral blood.

MATERIAL AND METHOD

We studied 49 patients with idiopathic retinal detachment. Leucocyte migration inhibition, proliferation of T-lymphocytes after PHA stimulation, nonspecific suppressor activity induced by Con A, T-lymphocytes IL-2 production and basophils histamine release were assessed.

RESULTS

Lymphocytes obtained from patients with retinal detachment lasting 3-4 weeks exhibited in vitro in the presence of SRF: increased ability to produce IL-2, increased proliferation after PHA stimulation and increased nonspecific T-suppressor activity induced by Con A. SRF enhanced also leucocyte migration inhibition and release of histamine from basophils.

Phase-contrast microscopic studies using cinematographic techniques and scanning electron microscopy on IgE-mediated degranulation of cultured human mast cells

BACKGROUND

Isolating human mast cells is a laborious procedure. Recently, cultured human mast cells raised from umbilical cord blood cells have become available. It is necessary to investigate whether IgE-mediated activation of these cells is mediated by exocytosis.

OBJECTIVE

To verify IgE-mediated activation of these cultured human mast cells morphologically.

METHODS

The mast cells were raised from human umbilical cord blood cells in the presence of stem cell factor and interleukin-6. IgE-sensitized cultured human mast cells were activated by anti-IgE, and morphological changes of the cells were examined under phase-contrast microscopy using cinematographic techniques and scanning electron microscopy. Histamine release from the cells was measured with high-performance liquid chromatography.

RESULTS

Under the condition in which a significant histamine release was observed from the mast cells, phase-contrast microscopy showed that the cultured human mast cells became swollen and extruded granules. Scanning electron microscopy disclosed the extrusion of smooth and round bodies from pores formed on the activated mast cell surface.

CONCLUSION

IgE-mediated histamine release from cultured human mast cells is accompanied by exocytosis morphologically, indicating that cultured human mast cells will help in studying the functional properties of human mast cells.

Identification of a basophil leukocyte interleukin-3-regulated protein that is identical to IgE-dependent histamine-releasing factor

This study aimed to identify basophil leukocyte proteins associated with interleukin (IL)-3 and/or anti-IgE activation by two-dimensional (2-D) gel electrophoresis. We noticed one particular protein showing increased synthesis after recombinant human (rh)IL-3 and, to a lesser extent, anti-IgE stimulation. The protein was also present in the culture medium in increased amounts after rhIL-3 stimulation. On the basis of comigration with proteins in published 2-D gel electrophoresis databases and immunoblotting with a specific monoclonal antibody, we identified this protein as translationally controlled tumor protein (TCTP), also known as p23 or IgE-dependent histamine-releasing factor. The antibody was shown to be specific for TCTP/IgE-dependent histamine-releasing factor by blotting on 2-D gels of proteins from human lymphocytes and the human basophilic cell line KU812, followed by N-terminal amino-acid sequencing of the bound protein. Densitometric analysis of the gels showed that the synthesis of IgE-dependent histamine-releasing factor in human basophil leukocytes was dose dependent upon rhIL-3 stimulation with an optimum of 100 ng/ml. The level of the protein in the medium was also highest at an optimal rhIL-3 concentration of 100 ng/ml. Supernatants from cultured basophils were able to stimulate histamine release from other basophils. This histamine release was decreased by precipitation of TCTP/IgE-dependent histamine-releasing factor from these supernatants.

IL-4 secretion and histamine release by human basophils are differentially regulated by protein kinase C activation

The role of protein kinase C (PKC) activation was investigated in the secretion of interleukin-4 (IL-4) protein by human basophils. Phorbol myristate acetate (PMA) induced little to no detectable IL-4 protein in culture supernatants, despite being a potent secretagogue of histamine release by basophils. In fact, the secretion of IL-4 by basophils stimulated with ionomycin alone was down-regulated (30-70%) with the simultaneous addition of PMA. In peripheral blood lymphocytes (PBL), however, the combination of ionomycin and PMA were highly synergistic, resulting in maximum IL-4 release but at a slower rate. PKC inhibitors reversed these effects on IL-4 secretion. In sharp contrast to its inhibitory effect on IL-4 protein secretion, PMA did not block the accumulation of IL-4 mRNA in basophils activated by ionomycin. These data suggest that there are marked differences in the regulatory processes for IL-4 transcription, translation, or secretion between basophils and lymphocytes.

Autoregulation of histamine release in medulla oblongata via H3-receptors in rabbits

The release of histamine (HA) from the rostral ventrolateral medulla (RVL), the raphe nuclei (nR), and the solitary nucleus (nTS) was investigated in anesthetized rabbits using microdialysis and high-performance liquid chromatography. HA release upon electrical stimulation of the posterior hypothalamus (PH), where histaminergic cell bodies are located, was increased to 168% of the baseline level in the RVL (n = 6), 139% of the baseline level in the nR (n = 5), and 166% of the baseline level in the nTS (n = 4). Upon perfusion of thioperamide, an H3-receptor antagonist, via a microdialysis probe, HA release from the RVL, nR and nTS increased. The increase in HA release from the RVL, nR and nTS following thioperamide perfusion was suppressed by co-perfusion of thioperamide and an H3-receptor agonist, imetit. We found that HA is released from the RVL, nR and nTS, that the HA release from all three areas is increased upon stimulation of the PH, and that the HA release is locally influenced in opposite directions by thioperamide and imetit. These results suggest that HA release in the medulla oblongata is controlled by the PH and that H3-receptors participate in the autoregulation of HA release by providing negative feedback locally. Autoregulation of HA release via H3-receptors may be important for maintaining tonic output to the sympathetic nervous system.

Purification of human colonic and gastric mast cells

We have developed a method to purify mast cells from enzymatic isolates of human colonic mucosa (HCM) and submucosa/muscle (HCS), and gastric mucosa (HGM) and submucosa/muscle (HGS). The purification of mast cells from these enzymatic isolates involves positive affinity-magnetic selection of mast cells using a monoclonal antibody specific for the c-kit receptor tyrosine kinase (CD117). The monoclonal antibody is coupled to Dynabeads for positive affinity selection of c-kit receptor positive cells which includes mast cells. This selection procedure generates preparations of mast cells from HCM, HCS, HGM and HGS that are 80% pure. The purified mast cells were microscopically normal and viable (> 85%). The functionality of purified mast cells was examined by studying the effect of anti-human IgE, Concanavalin A (Con A) and calcium ionophore A23187 on histamine release. These results show that this purification procedure generates microscopically normal, viable and functional mast cells. This method of purifying human gastrointestinal tissue mast cells may be a valuable tool for the further study of mast cell heterogeneity and the role of mast cells in the gastrointestinal tract.

Studies on mast cells and histamine release in psoriasis: the effect of ranitidine

The purpose of this study was to investigate histamine and skin mast cells in psoriasis before and during 6 months of treatment with high-dose ranitidine. Sixteen psoriasis patients, presenting a mean PASI score of 15.4, were compared with 13 age- and sex-matched healthy controls. Resting extracellular skin levels of histamine and histamine release to mast cell secretagogues, as measured by the microdialysis technique, were increased in involved psoriasis skin compared to normal skin in the controls. Plasma histamine, but not basophil histamine release, was significantly increased in the patients. Mast cells and lymphocytes were significantly increased in numbers in involved versus non-involved skin in the patients, the lymphocytes being predominantly T-lymphocytes expressing HLA-DR activation. During 6 months of ranitidine treatment, mean PASI score of 15.4 decreased to 5.8. The lymphocyte infiltration, but not mast cell numbers, was significantly reduced during treatment, and histamine release to mast cell secretagogues was normalized. These observations suggest that skin mast cells in active psoriasis are functionally hyperreactive. The biochemical findings together with the clinical effect of ranitidine indicate that histamine may be involved in the pathophysiology of psoriasis.

The M2 muscarinic receptor antagonist methoctramine activates mast cells via pertussis toxin-sensitive G proteins

Methoctramine, a selective M2 muscarinic cholinergic receptor antagonist, has been reported to activate phosphoinositide breakdown at high concentrations. Its polyamine structure suggests a putative activation of guanine nucleotide-binding proteins (G proteins). Incubation of methoctramine with rat peritoneal mast cells resulted in a dose-dependent noncytotoxic histamine release, with an EC50 of 20 microM and a maximum effect at 1 mM. Atropine, pirenzepine and HHSiD neither inhibited methoctramine-induced histamine release nor stimulated histamine release. Histamine release and inositol phosphates generation induced by methoctramine were both inhibited by pertussis toxin pretreatment. Benzalkonium chloride, a selective inhibitor of histamine secretion induced by basic secretagogues, inhibited the secretory response to methoctramine. [p-Glu5, D-Trp7,9,l0]-SPs5-11 (GPAnt-2), a well-characterized antagonist of G proteins, blocked the methoctramine-induced histamine release when the antagonist was allowed to reach its intracellular target by streptolysin O-permeabilization. The response to methoctramine was prevented by the hydrolysis of sialic acid residues of the cell surface by neuraminidase. The response of mast cells was restored by permeabilization of the plasma membrane. These results demonstrate that methoctramine, following its entry into the cell and the involvement of pertussis toxin-sensitive G proteins, activates phosphoinositide hydrolysis leading to mast cell exocytosis.

Neurohormonal stimulation of histamine release from neuroendocrine cells of the human adenomatous prostate

BACKGROUND

Neuroendocrine cells (NE) constitute a population of highly specialized cells in prostatic glands; histamine has never been described in these cells. This article shows the presence and the regulation of release of histamine in NE.

METHODS

In 21 prostatic adenomas, NE were identified by specific antisera against neuroendocrine markers (chromogranin-A, synaptophysin), histamine, and histidine decarboxylase (HDC); a rate HDC-cDNA probe was used to detect this enzyme by in situ hybridization.

RESULTS

Immunoreactive cells for chromogranin-A, histamine, and HDC were found among luminal epithelial glandular cells. Similar cells were also labeled with the HDC-cDNA probe. Glandular cells, isolated from prostatic adenomas, were shown to contain histamine (7-40 pmol/mg cellular protein). L(-) norepinephrine causes a time-dependent (t1/2 = 22 min) histamine release; the alpha 1-receptor antagonists WB-4101 and YM-617 specifically inhibited this release, in agreement with a mediation by alpha 1-adrenoreceptor subtype.

CONCLUSIONS

There is some evidence for the presence in prostatic adenomas of histamine-forming cells of neuroendocrine type; histamine release from these cells is under the control of alpha 1-adrenoreceptor subtype.

Histamine and tissue fibrinolytic activity in duodenal ulcer disease

Patients with duodenal ulcer have lower gastroduodenal mucosal histamine and a reduced tissue fibrinolysis at the ulcer edge. In the duodenal mucosa fibrinolysis is regulated by the tissue-type and urokinase-type plasminogen activators; and inhibitors type 1 and type 2. Trends across ordered groups leading from mucosa of nonulcer control subjects, "normal" mucosa of ulcer patients, to ulcer edge were found in tissue-type plasminogen activator concentration, histamine concentration, and histamine methyltransferase activity. Concentrations of tissue-type activator, inhibitor type 1, and histamine were significantly lower at ulcer edge than at normal. An inverse correlation was found between histamine methyltransferase and plasminogen activator activities, methyltransferase and tissue-type activator, and methyltransferase and histamine. These results support the hypothesis that in active ulceration, reduction in tissue fibrinolytic activity is closely associated with enhanced release and metabolism of histamine.