Modulation of the spontaneous histamine release by adrenergic and cholinergic drugs

An In Vivo Definition of Brain Histamine Dynamics Reveals Critical Neuromodulatory Roles for This Elusive Messenger

Histamine is well known for mediating peripheral inflammation; however, this amine is also found in high concentrations in the brain where its roles are much less known. In vivo chemical dynamics are difficult to measure, thus fundamental aspects of histamine's neurochemistry remain undefined. In this work, we undertake the first in-depth characterization of real time in vivo histamine dynamics using fast electrochemical tools. We find that histamine release is sensitive to pharmacological manipulation at the level of synthesis, packaging, autoreceptors and metabolism. We find two breakthrough aspects of histamine modulation. First, differences in H3 receptor regulation between sexes show that histamine release in female mice is much more tightly regulated than in male mice under H3 or inflammatory drug challenge. We hypothesize that this finding may contribute to hormone-mediated neuroprotection mechanisms in female mice. Second, a high dose of a commonly available antihistamine, the H1 receptor inverse agonist diphenhydramine, rapidly decreases serotonin levels. This finding highlights the sheer significance of pharmaceuticals on neuromodulation. Our study opens the path to better understanding and treating histamine related disorders of the brain (such as neuroinflammation), emphasizing that sex and modulation (of serotonin) are critical factors to consider when studying/designing new histamine targeting therapeutics.

Catecholaminergic and acetylcholine esterase containing nerves of cranial and spinal dura mater in humans and rodents

The innervation of cranial and spinal dura mater in humans and rodents was studied by examining several dural zones (vascular, perivascular, intervascular) in different regions. Characterization and distribution of dural acetylcholinesterase-positive nerve fibers, catecholaminergic nerve fibers, and mast cells are analyzed and discussed. The results of chemical and surgical sympathectomy as well as the relationships between catecholaminergic nerve fibers and mast cells are studied. Our results are discussed in the light of possible implications in the physiopathology of dural algic syndromes including cephalalgia and spinal pain.

Cerebral dura mater and cephalalgia: relationships between mast cells and catecholaminergic nerve fibers in the rat

The aim of the present study was to examine whether mast cells have the same variations as the related catecholaminergic nerve fibers. Chemical sympathectomy or surgical removal of right superior cervical ganglion induced a rapid decrease of fluorescence in both nerve fibers and mast cells, as confirmed by quantitative analysis (nerve fibers 19 +/- 1.1 vs 1.3 +/- 0.6; mast cell 10.8 +/- 1.9 vs 2.1 +/- 0.3). The results of quantitative analysis after nerve fiber stimulation (electrical), however, showed an increase of the fluorescence in both the nerve fibers and the mast cells (nerve fibers 43.4 +/- 2.4; mast cells 18.6 +/- 1.6). Moreover, we found that the basal zone is more innervated (regarding catecholaminergic nerve fibers) than the apical one, and that the fluorescence level decreases passing from the vasal zone to the perivasal and intervasal zones. Further studies are needed in order to clarify the role of fluorescent nerve fibers and mast cells of cerebral dura mater in cephalalgia.

Augmentation of allergic reactions by several pesticides

The augmentative effects of several pesticides on histamine release from mast cells of rats that had been sensitized passively by anti-dinitrophenol (DNP) monoclonal IgE antibodies were investigated in vitro. Various pesticides, especially phenthoate (PAP), chlornitrofen (CNP) and paraquat (PQ), increased histamine release. This increase was not observed in histamine release with non-antigen or induction by calcium ionophore A23187 or compound 48/80. Passive cutaneous anaphylaxis (PCA) was examined, and an increase of PCA was observed with PAP and PQ, but not with CNP, while an increase of tumor necrosis factor-alpha (TNF-alpha) production was observed with CNP and PQ, but not PAP. These results suggest that various pesticides as environmental pollutants exacerbate allergic diseases.

Acetylcholine via muscarinic receptors inhibits histamine release from human isolated bronchi

Human bronchi were incubated in organ baths to measure histamine release. The calcium ionophore A23187 (10 mumol/L; 1 min) stimulated histamine release by 148 +/- 28% (n = 11) above the prestimulation level but was ineffective in epithelium-denuded bronchi. Neither bradykinin (0.1 mumol/L) nor compound 48/80 (10 micrograms/ml) triggered the release of histamine from epithelium-intact bronchi. Acetylcholine did not affect spontaneous histamine release (about 2 nmol/g x 5 min) but inhibited A23187-evoked histamine release in an atropine-sensitive manner. Already a concentration as low as 0.1 nmol/L acetylcholine was effective, the maximal inhibition (by 89%) occurred at 100 nmol/L, whereas a concentration of 10 mumol/L acetylcholine was ineffective. Oxotremorine (1 nmol/L), a stable agonist at muscarinic receptors, suppressed stimulated histamine release completely. Physostigmine (0.1 mumol/L), an acetylcholinesterase inhibitor, reduced A23187-evoked histamine release by 58%. Antihuman IgE antibody stimulated histamine release by 127 +/- 30% (n = 6) above the prestimulation level. Acetylcholine (100 nmol/L) inhibited also the immunologically evoked histamine release by 70%. In conclusion, the present experiments provide a model to characterize mast cells that are localized in or close to the airway surface epithelium. Acetylcholine via muscarinic receptors strongly inhibits the releasability of these mucosal mast cells being among the first cells to interact with inhaled antigens and environmental agents. The inhibitory action of physostigmine indicates the involvement of endogenous, probably non-neuronal acetylcholine expressed in airway epithelial cells.

Spontaneous histamine release and histamine content in normal subjects and subjects with asthma

Spontaneous histamine release (SHR) from basophils by simple incubation at 37 degrees C for 60 minutes and histamine content of basophils were assessed in normal subjects, patients with asthma, and methacholine-sensitive subjects without asthma (NAMS). SHR from basophils of normal subjects did not exceed 10% of the total histamine. A significantly higher SHR was observed in basophils from subjects with asthma than from normal subjects (p less than 0.002). Basophil SHR in patients with asthma not receiving medication was significantly greater than that in patients with asthma receiving medication (p less than 0.05). SHR from basophils in NAMS subjects was similar to that in normal subjects. SHR was highly dependent on temperature and Ca++ and Mg++ ions and appeared to be a slower event than anaphylactic release. The mean histamine content per basophil from normal subjects was 1.48 +/- 0.13 pg (mean +/- SEM). Basophils from subjects with asthma contained significantly less histamine than basophils from normal subjects (p less than 0.002). Histamine content per basophil from NAMS subjects was slightly lower than histamine content per normal basophil. No apparent relationship was found between the magnitude of SHR and the histamine content per basophil in the patients with asthma not receiving medication. Hypersensitivity to food or exercise does not appear to be essential for high SHR. High SHR appears to bear little, if any, relationship to cell damage or cell death. High SHR may be a factor that could serve as a marker for bronchial asthma. Further studies are needed to define the clinical relationship and pathophysiologic mechanism of SHR.

The actions of histamine in cat and rabbit superior cervical ganglia

Depolarization of the cat superior cervical ganglion (SCG) evoked by histamine was antagonized by mepyramine. Histamine-induced depolarization, indicated by changes in the negative and positive afterpotentials of ganglionic action potentials, was decreased by pretreatment with aminophylline. In the cat SCG, histamine evoked stimulus bound decremental oscillatory potentials (SBDOP). In the rabbit SCG, only depolarization and no SBDOP were observed after the administration of histamine. Histamine-induced SBDOP were increased by isoprenaline and decreased by Leu-enkephalin pretreatment. Our results indicate that histamine evokes depolarization and an increase in excitability of the cat SCG which seems to be mediated by H1-receptors.

Adrenergic activity on rat pleural and peritoneal mast cells. Loss of beta-receptors during the purification procedure

Adrenergic agonists inhibit the release of histamine from rat pleural and peritoneal mast cells stimulated with compound 48/80 to a degree dependent on their beta-activity. Isoprenaline takes part in a stereoselective inhibitory action in the range 10(-7)-10(-4) M. Adrenaline induces a similar response pattern, with inhibition at higher concentrations. The response profile, but not the maximum values of inhibition, is clearly dependent on the concentration of the histamine releaser. Noradrenaline by itself is a histamine releaser, no stereoselectivity being observed. In the presence of compound 48/80 it takes part in a non-stereoselective inhibitory reaction at low concentrations. Inhibition of histamine release by isoprenaline was antagonized by 10 or 100 microM propranolol except at the highest isoprenaline concentration (1 mM). Both atenolol and propranolol nullified the inhibitory activity of noradrenaline, but not the increased histamine release it induces at higher concentrations (at least when acting in conjunction with compound 48/80). When rat mast cells are purified through Percoll, a change in their response profiles is observed. Isoprenaline and adrenaline by themselves elicit non-specific release of histamine; with compound 48/80, release is additive in the case of isoprenaline and supra-additive in the case of adrenaline. Results point to the loss of beta-adrenergic inhibitory activity after purification.

The release of histamine by parasympathetic stimulation in guinea-pig auricle and rat ileum

Two preparations, a segment of rat ileum and the vagally innerved guinea-pig auricles, have been used in an analysis of the responses to vagal or to electrical field stimulation. The responses to parasympathetic stimulation were depressed by atropine and by tetrodotoxin, and potentiated by eserine. Supramaximal stimulation (10-20 Hz) resulted in increased release of acetylcholine and histamine, both in rat ileum and guinea-pig auricles. The release of histamine after parasympathetic stimulation did not exhibit tachyphylaxis, and it was not reproduced by non-parasympathetic stimuli. In both preparations, atropine produced a significant, dose-related reduction of histamine measured in the bath fluid after stimulation, while eserine increased histamine output. A significant diminution of mast cell granules metachromasia was observed in guinea-pig auricles and in rat intestine after parasympathetic stimulation. The possibility is discussed that acetylcholine released by parasympathetic stimulation would in turn evoke the secretion of histamine from tissue mast cells.

Plasma histamine and catecholamines during carbachol-induced bronchoconstriction in normal subjects

To determine (1) whether changes in plasma histamine occurred during provoked bronchospasm and (2) if so, whether such changes could be related to variations in plasma catecholamines, venous plasma histamine and catecholamines were measured during a dose-response carbachol challenge in eight healthy volunteers. A significant rise in plasma histamine was observed, whereas induced bronchoconstriction was small, 80% +/- 4% of initial specific airway conductance. There was no further increase in plasma histamine, whereas induced bronchoconstriction became more marked (70%, 60%, and 50% of specific airway conductance initial value). Plasma catecholamines did not change throughout the study. We conclude that mast cell degranulation occurs during a carbachol challenge, and that the variations in plasma histamine are not related to changes in plasma catecholamines.

Mediator release from isolated rat ileum in response to field stimulation

The effect of electrical field stimulation on mediator release from the isolated rat ileum was evaluated by recording the muscle responses and by measuring acetylcholine and histamine appearing in the perfusion fluid. In the presence of cholinesterase inhibitors, supramaximal field stimulation (10 Hz) resulted in twitch responses accompanied by an increased release of acetylcholine. The resting output of histamine was measurable also in the absence of inhibition of cholinesterases, and neatly increased during electrical stimulation. Atropine produced a dose-related decrease in the release of histamine from electrically stimulated muscle, while eserine extends the time-course of the contractile response and of the histamine release as well. The results are discussed in the context of the role ascribed to acetylcholine as a physiological modulator of histamine release.

The interaction of cholinomimetics, peptides and compounds 48/80 on histamine secretion from the mast cell

The mechanism of selective, non-immunological histamine release from mast cells, caused by various endogenous substances, is not clearly understood. Since in vivo experiments indicate that the local control of secretory cells is influenced by acetylcholine and peptides, we investigated whether the secretion of histamine is similarly regulated in the mast cell. Experiments were performed with peritoneal cavity cell suspensions (PCS) of the rat. The endogenous polypeptide substance P, compound 48/80 and a non-hydrolysable cholinomimetic agonist, carbachol, were used. The concentrations of the drugs were kept low to avoid non-specific histamine release caused by morphological damage of mast cells. It was found that: (1) carbachol (2 X 10(-5) M) did not release histamine from PCS, (2) substance P (6.5 X 10(-6) M) released histamine and this effect was increased by the addition of carbachol (2 X 10(-5) M); the effect of carbachol was inhibited by atropine , (3) carbachol (2 X 10(-5)M) did not increase histamine release caused by compound 48/80 (0.02 micrograms/ml). From these experiments it may be concluded that activation of peptidergic receptor(s) can cause histamine release from mast cells and that muscarinic agents may be involved in the regulation of the(se) receptor(s).

Muscarinic cholinergic receptor binding in rat mast cells

Specific [3H]-QNB binding was present in isolated, purified, intact rat mast cells and in crude membrane preparations. The binding is saturable, time- and temperature-dependent. Cholinergic agents inhibit selectively the binding: atropine is the most effective of the antagonists while oxotremorine is the most potent of the muscarinic agonists. It is concluded that rat mast cells are provided with muscarinic cholinergic receptors.

Mast cell receptors controlling histamine release: influences on the mode of action of drugs used in the treatment of adverse drug reactions

In drug-induced allergic diseases of the immediate type (anaphylactic and anaphylactoid reactions), the primary target cells are tissue mast cells, which discharge their granular content upon interaction with different secretagogues (immunological releasers; histamine liberators) on specific plasma membrane receptors. Experiments are reviewed here which report that IgE-mediated histamine release from mast cells, and the secretion of histamine induced by non-immunological secretagogues (dextran; compound 48/80; acetylcholine) are blocked by beta-adrenoceptor and H2-receptor agonists, their inhibiting effect being surmountable by beta-adrenoceptor blocking drugs and by anti-H2-antihistamines. Specific radioligands ([3H]-dihydroalprenolol; [3H]-cimetidine) binding to rat mast cell membranes points to the possibility that inhibition of histamine release is brought about by the activation of mast cell beta-adrenoceptors and H2-receptors. Drugs used in therapy of anaphylactic or anaphylactoid reactions may act either on tissue receptors, competing with released mediators, or by inhibiting the release of allergic mediators from mast cells, on activation of specific receptors located in mast cell plasma membranes.

The effects of atropine on anaphylactic shock in the guinea-pig

The effects of atropine, 2 mg/kg i.v., on anaphylactic shock were studied in guinea-pigs sensitized to ovalbumin. Atropine only moderately reduced (--31%) the increase in pulmonary resistance observed and slightly prolonged (+26%) the survival time in pretreated animals compared with controls. These effects, however, were no statistically significant. The drug temporarily improved ventilation but had no influence on haematosis. On the other hand, atropine significantly reduced the amount of histamine released (--60%) and of GMPc synthetized in the lung (--21%). The levels of AMPc and prostaglandins E1, E2 and F2 alpha remained comparable to those of control animals. These results suggest that the reflex-induced action of the cholinergic system during anaphylaxis primarily affects large-calibre airways and that the role of acetylcholine in severe reactions is moderate when compared with the direct action of other mediators.

Correlation between cholinergic histamine release and quinuclidinyl-benzilate ([3H]-QNB) binding in mast cell membranes

Isolated purified rat mast cells release histamine when exposed to acetylcholine according to a different pattern of sensitivity. No correlation was found between the release of histamine evoked by acetylcholine and the high affinity binding of [3H]-quinuclidinyl-benzilate (QNB), a specific cholinergic muscarinic ligand, to rat mast cell membranes, since QNB binding was the same in membrane isolated from cells which were sensitive or insensitive to acetylcholine. In murine neoplastic mast cells, a negative correlation was found between histamine release and [3H]-QNB binding, as no evidence of specific [3H]-QNB binding was present in murine neoplastic mast cell membranes which, accordingly, do not release histamine when exposed to acetylcholine. It is concluded that murine neoplastic mast cells are not provided with muscarinic cholinergic receptors. In rat mast cells, muscarinic cholinergic receptors are always present, but not always coupled with the effector mechanisms triggering the exocytosis.

Characteristics of histamine release evoked by acetylcholine in isolated rat mast cells

1. Histamine secretion from rat mast cells occurs in the presence of nanomolar concentrations of acetylcholine. 2. Intact glycolytic and oxidative metabolism is required for the acetylcholine-induced histamine secretion. Removal of extracellular glucose, hypoxia, cyanide and monoiodoacetate almost completely inhibit the secretion. 3. The secretion of histamine is dependent on the extracellular H ion concentration and is blocked when the cells are exposed to Na-deficient media. 4. The order of potency of cholinrgic agonists in evoking the secretion of histamine is oxotremorine > acetylcholine > choline > carbamycholine > nicotine. 5. Atropine competitively blocks the acetylcholine-induced histamine secretion, indicating the presence of cholinergic muscarinic receptors on mast cells. 6. Dibutyryl cyclic AMP and adrenaline inhibit the acetylcholine-induced histamine secretion, indicating a regulatory function afforded by cyclic nucleotides in the cholinergic histamine release.

Inhibition of cholinergic histamine release in rat mast cells

Adrenaline inhibits the acetylcholine-evoked histamine release from isolated purified rat mast cells, in a dose-dependent fashion. The inhibitory effect of adrenaline is reversed by preincubating the cells with a beta-blocker, aprenolol, but not by preincubating them with an alpha-blocker, phentolamine. These results were confirmed by observations using an electron microscope and they suggest that adrenaline inhibits the cholinergic histamine release from rat mast cells acting upoon beta-receptors.

Failure of acetylcholine to release histamine from rat mast cells

The action of various salts of acetylcholine on isolated mast cells from Wistar and F1 hybrids of Wistar and August rats was investigated. None of the acetylcholine salts within the concentration range 10(-12) M to 10(-2) M was able to release histamine either from Wistar or from hybrid mast cells. Compound 48/80, used as a control, was active in both cases. The results obtained are in opposition to some recent reports. The possible reasons for these contradictions are discussed.