Histamine release from rat mast cells by Vibrio vulnificus protease

Abstract Vibrio vulnificus protease (VVP) stimulated histamine release from isolated mast cells in a dose- and temperature-dependent manner within a range of 0.2–4.0 μ g/0.5 ml. Histamine release was accompanied by degranulation, and no leakage of lactate dehydrogenase from cells was observed, indicating that the histamine release was not due to cytolysis but to exocytosis. This release, completed within 30 s at 37°C, suggested that the mechanism of action of VVP on mast cells is different from that of other proteases, such as trypsin or α-chymotrypsin, which release histamine from the cells slowly.     

Histamine and TNF-alpha release by rat peritoneal mast cells stimulated with Trichomonas vaginalis

Mast cells have been reported to be predominant in the vaginal smears of patients infected with T. vaginalis. In this study, we investigated whether T. vaginalis could induce mast cells to migrate and to produce TNF-alpha and histamine. Rat peritoneal mast cells (RPMC), a primary mast cell, were used for the study. T. vaginalis induced an increase in chemotactic migration of the mast cells toward excretory and secretory product (ESP) of T. vaginalis, and the mast cells activated with T. vaginalis showed an increased release of histamine and TNF-alpha. Therefore, mast cells may be involved in the inflammatory response caused by T. vaginalis.     

Renal actions of dendroaspis natriuretic peptide in rabbits

Dendroaspis natriuretic peptide (DNP) is one of four members of the natriuretic peptide family sharing functional and structural properties. The purpose of the present study was to elucidate the physiological role of DNP on renal functions and its cellular mechanism in the rabbit kidney. DNP (5 μg/kg/min) infused intravenously increased urine volume and urinary excretion of electrolytes. These renal actions induced by DNP were more pronounced than those caused by atrial natriuretic peptide (ANP). We compared profiles of (125)I-ANP and (125)I-DNP by reverse-phase HPLC during incubation in rabbit plasma at 37°C for 1, 2, and 4h. While (125)I-ANP was quickly degraded within 1h, (125)I-DNP was still stable in plasma for 4h. DNP induced the greatest cyclic guanosine monophosphate (cGMP) production in the glomeruli in a dose-dependent manner, when compared to other renal structures including cortical tubules, outer medullary tubules, and inner medullary tubules. Affinity cross-linking analysis revealed NPR-A is selective receptor for DNP in glomeruli. Forskolin, a stimulator of adenylyl cyclase, significantly decreased cGMP production in the renal glomeruli but not in the renal medulla. In summary, DNP is a more effective activator of renal functions than ANP, possibly because of the degradation resistance of DNP against the endogenous peptidases in plasma or tissues. These findings suggest that DNP plays a pivotal role as a renal regulating peptide via specific natriuretic peptide receptors with a guanylyl cyclase domain.     

Histamine release from mouse and rat mast cells cultured with supernatants from chronic murine graft-vs-host splenocytes.

There is growing interest in studying pathways of mast cell activation. In a mouse model of chronic graft-vs-host disease (cGVHD) extensive mast cell activation and degranulation occurs in vivo coincident with the development of dermal fibrosis. An interesting feature of this model is that the mast cell reaction is slow to develop, occurring over a period of weeks and waning by 300 days. The aim of our work was to investigate the effects of supernatants from splenocytes of such cGVHD mice (cGVHD sups) on mouse and rat peritoneal mast cells cocultured with 3T3 skin fibroblasts. We found that cGVHD sups are able to release histamine from both mouse and rat cultured mast cells in a slow fashion. Histamine release became evident only after 5-8 days of coculture of the mast cells with the cGVHD supernatants and thereafter decreased to basal levels. Mast cell activation due to cGVHD supernatants was a noncytotoxic event as demonstrated by mast cell counts in the cocultures and by the ability of mast cells to exclude trypan blue. Mast cells that had been activated by incubation with the cGVHD sups were as responsive to stimulation with either anti-IgE antibodies or compound 48/80 as were mast cells incubated with control sups. Supernatants from mice early in GVHD (Days 11-28) were most active in promoting histamine release. Supernatants from spleens of mice which had GVHD for 290 days and where the mast cells had returned to full granulation in vivo were inactive. This is the first in vitro study demonstrating slow mast cell histamine release instituted by other cells, namely the splenocytes of cGVHD mice.     

Histamine secretion from permeabilized mast cells by calcium

A transient increase in the permeability of the mast cell membrane was caused by the exposure of the cells to low concentrations of saponin, 5 or 10 micrograms/ml. These concentrations had very little effect in the absence of calcium but caused 35 to 50% histamine release, having the character of a secretory response, when 0.25 mM or more calcium was added to the medium. The dose-response curve was steep between 25 microM and 250 microM calcium and tended to flatten with higher concentrations. The release was associated with a pronounced increase in calcium uptake, which was faster than the histamine release. The membrane changes were slight as indicated by only 7 to 12% leakage of lactate dehydrogenase and by the absence of any detectable change in the electron micrographs. The transient nature of the membrane change is shown by the following experiment. When the cells were first exposed to saponin in the absence of calcium, the amount of histamine released by the subsequent incubation with calcium varied inversely with the time interval that elapsed before calcium was added. If calcium was added after 15 minutes no histamine release occurred. When calcium uptake was studied in the same manner, the stimulation of calcium uptake in saponin-treated cells also declined progressively with increasing intervals after the exposure to saponin when calcium was added. Stimulation of both histamine release and calcium uptake was inhibited by antimycin A, the inhibition curves with 10(-9)M to 10(-7)M antimycin A being similar. The effect on the calcium uptake by itself could explain the inhibition of histamine release. But the release was also inhibited by the calmodulin antagonists, W-7 and mepacrine, suggesting that the influx of calcium in the permeabilized cells acts primarily through calmodulin-mediated enzyme activation.     

Immunolocalization of atrial natriuretic peptide in mast cells of human and rat pericardium

It is known that various heart disorders are accompanied by an elevated level of atrial natriuretic peptide (ANP), a regulator of cardiovascular homeostasis, in the pericardial fluid. Which cells produce ANP in the pericardial cavity is unclear. Using immunoelectron microscopy, we examined ANP localization in human and rat pericardium. ANP-immunobinding material was found in granules of mast cells (MC) localized in pericardial connective tissue. In rat pericardium, the average MC size is 6.5 × 12.5 μm and the MC density is about 50 cells per 1 mm² section area. For the human pericardium, these parameters are 9.1 × 13.6 μm and 10 cells per 1 mm², respectively. The results show that MCs are probably implicated in the pericardial endocrine function and in controlling the ANP level in the pericardial cavity.     

Stimulation by volume expansion of atrial natriuretic peptide release from perfused rat heart

The release of immunoreactive (ir-) rat atrial natriuretic peptide (rANP) with volume expansion in in situ retrograde perfused rat heart was examined. The volume expansion induced by the infusion of the perfusion medium into the right atrium increased the mean right atrial pressure and the ir-rANP release without changing the rate of the heart beat. There was a significant correlation between the peak values of ir-rANP release and those of mean atrial pressure. The bilateral cervical vagotomy did not effect the ir-rANP release induced by the volume expansion. Therefore, it is highly likely that the stimulatory effect of volume expansion on rANP release is due to, at least in part, the atrial distension accompanied by an increase in mean atrial pressure, not involving a vagal system.     

Induction of histamine release from rat mast cells by bradykinin analogues

Independently of their agonistic or antagonistic activity on different isolated tissue preparations, the kinin analogues investigated induce histamine release on rat peritoneal mast cells. The effectivity of most compounds is 10 to 100 times higher than that of bradykinin. Beside the positively charged amino acids, the elongation at the N-terminus with hydrophobic amino acids and the replacement of amino acids in the bradykinin sequence (especially at position 7) with aromatic residues is important for a high histamine-releasing activity.     

Response of cardiac mast cells to atrial natriuretic peptide

Previously, our laboratory demonstrated that cardiac mast cell degranulation induces adverse ventricular remodeling in response to chronic volume overload. The purpose of this study was to investigate whether atrial natriuretic peptide (ANP), which is known to be elevated in chronic volume overload, causes cardiac mast cell degranulation. Relative to control, ANP induced significant histamine release from peritoneal mast cells, whereas isolated cardiac mast cells were not responsive. Infusion of ANP (225 pg/ml) into blood-perfused isolated rat hearts produced minimal activation of cardiac mast cells, similar to that seen in the control group. ANP also did not increase matrix metalloproteinase-2 activity, reduce collagen volume fraction, or alter diastolic or systolic cardiac function compared with saline-treated controls. In a subsequent study to evaluate the effects of natriuretic peptide receptor antagonism on volume overload-induced ventricular remodeling, anantin was administered to rats with an aortocaval fistula. Comparable increases of myocardial MMP-2 activity in treated and untreated rats with an aortocaval fistula were associated with equivalent decreases in ventricular collagen (P < 0.05 vs. sham-operated controls). Cardiac functional parameters and left ventricular hypertrophy were unaffected by anantin. We conclude that ANP is not a cardiac mast cell secretagogue and is not responsible for the cardiac mast cell-mediated adverse ventricular remodeling in response to volume overload.     

Histamine H-1 receptors on rat peritoneal mast cells

In order to characterize the receptor subtype involved in histamine stimulation of increased cyclic AMP levels in rat mast cells with consequent impairment of anaphylactically induced mediator release, the binding of the H-1 receptor antagonist [³H] pyrilamine to mast cells was examined. Pyrilamine bound rapidly, in a saturable and reversible fashion, and with increased binding at 4°C as compared with 21°C and 37°C. [³H] Pyrilamine binding was displaced by H-1 antagonists (tripelnnamine > yrilamine ≧ iphenhydramine) > histamine > the H-2 antagonist, cimetidine. H-1 agonists displaced pyrilamine binding less efficiently than histamine but better than H-2 agonists. Rat mast cells have a single homogeneous population of low affinity (K_D = 222 ± 33 nM) H-1 receptors with a Bmax of 9.7 ± 2.3 pm/10⁶ mast cells and 5.4 ± 0.92 × 10⁶ binding sites per mast cell. Thus, the mast cell has an H-1 type histamine receptor which is probably involved in histamine-induced cyclic AMP increases.     

Concanavalin A-induced histamine release from normal rat mast cells.

Concanavalin A- (con A) induced release of histamine from normal rat mast cells was studied. In the presence of phosphatidylserine (PS) con A induced a concentration and temperature-dependent, noncytotoxic histamine release at con A concentrations ranging from 0.1 to 100 mug/ml. The optimal con A concentration, 100 mug/ml, caused a 27.3% (+/- 2.7 S.E.M.) net histamine release. Release began approximately 30 sec after addition of con A and was complete within 45 min. In the absence of PS, no net con A-induced release occurred. The effect of PS was concentration dependent from 1 to 100 mgg/ml. PS alone, however, did not cause histamine release. Binding studies indicated that mast cells bound up to 16 X 10(6) con A molecules per cell without histamine release. Upon removal of unbound con A and the addition of PS, normal histamine release occurred. Alpha-Methyl-D-mannose (50 mM) prevented both con A binding and histamine release and if added after Con A, caused a rapid cessation of histamine release and a reversal of con A binding. This study indicates several important advantages of the con A-induced histamine release system. Binding of con A to mast cells can be dissociated from histamine release by omitting PS from the medium. Release can then be induced by the addition of PS. Alpha-Methyl-D-mannose can be used to terminate rapidly the ongoing release reaction at any phase of the interaction. This system is potentially very useful for investigation of metabolic events during histamine release.     

Acetaldehyde induces histamine release from purified rat peritoneal mast cells

Acetaldehyde is a widely distributed compound in the human environment and it is also formed in the human body from various endogenous and exogenous sources, exogenous ethanol being the most important one. Many alcohol-associated hypersensitivity reactions, e.g. Oriental flushing reaction, appear to be attributable to acetaldehyde rather than to ethanol itself. The pathogenetic mechanism behind such hypersensitivity reactions has been suggested to be histamine release from mast cells or blood basophils. However, the direct effects of acetaldehyde on mast cells, the main source of histamine in a mammalian body, have not been studied. The aim of the present study was, thus, to evaluate whether physiological concentrations of acetaldehyde could release histamine from purified rat peritoneal mast cells. The effects of ethanol were studied similarly. The results show that acetaldehyde, already at a concentration of 50 microM, significantly increases the release of histamine from mast cells. Ethanol has a similar effect but only at molar concentrations. These results indicate that acetaldehyde may contribute to the development of various hypersensitivity reactions by directly increasing histamine release from mast cells.     

Ionophore A-23187 induced histamine release from rat mast cells and rat basophil leukemia (RBL-1) cells.

Ionophore A-23187 releases histamine from normal mast cells apparently by promoting Ca++ influx (Foreman et al, Nature 245: 249, 1973). In our hands at concentrations of greater than 0.2 mug/ml release occurs in 1 to 2 min, is blocked by metabolic inhibitors, and is unaccompanied by cytotoxicity (trypan-blue uptake, lactic dehydrogenase (LDH) release). At higher doses (0.5 mug/ml) histamine release is followed by significant cytotoxicity, but again Ca++ is required. In parallel studies, we examined cultured rat basophilic leukemia (RBL-1) cells. These cells, which apparently have normal surface receptors for IgE, contained approximately 700 ng histamine/10(6) cells but did not release histamine when IgE-mediated release was looked for. They do not respond to doses of ionophore which would be expected to give non-cytotoxic histamine release. At higher doses histamine release is preceded by progressive LDH release: LDH release is 75% complete at 5 min whereas 10 min are required for 75% maximal histamine release. This reaction requires Ca++ and is temperature dependent but is not inhibited by metabolic poisons (2-deoxyglucose, dinitrophenol, CN-). These studies suggest that either Ca++ does not enter into these cells normally or that one or more mechanisms which are ordinarily triggered by the changes in Ca++ flow are unresponsive in the RBL-1 cells. These studies also underline the importance of ruling out cytotoxicity in ionophore-induced phenomena.