Histamine and tele-methylhistamine quantification in cerebrospinal fluid from narcoleptic subjects by liquid chromatography tandem mass spectrometry with precolumn derivatization

An ultra-performance liquid chromatography tandem mass spectrometry (UPLC™–MS/MS) assay was developed for the simultaneous analysis of histamine, its major metabolite tele-methylhistamine, and an internal standard (N-tele-(R)-α-dimethylhistamine) from human cerebrospinal fluid (CSF) samples. The method involves derivatization of primary amines with 4-bromobenzenesulfonyl chloride and subsequent analysis by reversed phase liquid chromatography with mass spectrometry detection and positive electrospray ionization. The separation of derivatized biogenic amines was achieved within 3.5 min on an Acquity® BEH C₁₈ column by elution with a linear gradient of acetonitrile/water/formic acid (0.1%). The assay was linear in the concentration range of 50–5000 pM for each amine (5.5–555 pg/ml for histamine and 6.25–625 pg/ml for tele-methylhistamine). For repeatability and precision determination, coefficients of variation (CVs) were less than 11.0% over the tested concentration ranges, within acceptance criteria. Thus, the developed method provides the rapid, easy, highly sensitive, and selective requirement to quantify these amines in human CSF. No significant difference was found in the mean ± standard error levels of these amines between a group of narcoleptic patients (histamine = 392 ± 64 pM, tele-methylhistamine = 2431 ± 461 pM, n = 7) and of neurological control subjects (histamine = 402 ± 72 pM, tele-methylhistamine = 2209 ± 463 pM, n = 32).     

The reactivity of imidazole nitrogens in histidine to alkylation

Copper(II)-histidine complex was allowed to react at pH 6.0–6.1 at 22°C with bromoacetic acid. The reaction was followed by means of amino acid analysis of the histidine and N^im-carboxymethylhistidine derivatives. The results of the alkylation study indicate that the nucleophilic, active histidine molecule is coordinated to the copper(II) ion through the amino nitrogen and a carboxylate oxygen with the imidazole group turned away from the copper. This model of copper-bound histidine permitted the determination of the intrinsic nucleophilic activity of the imidazole nitrogens through their respective rate constants for alkylation. The tele-nitrogen is three times more reactive than the pros-nitrogen in the histidine and in the pros-carboxymethylhistidine-tele-carboxymethylhistidine systems. The carboxymethylation of copper(II)-histidine and bovine pancreatic ribonuclease have some analogies, which suggest that in pros-carboxymethylhistidine-119 ribonuclease the carboxylate unit of the alkylated histidine residue points into the active site.     

Simultaneous determination of histamine and Nτ-methylhistamine in human plasma and urine by gas chromatography-mass spectrometry

A new and sensitive method is described for the determination of histamine and N^τ-methylhistamine in human plasma and urine by gas chromatography-mass spectrometry. ¹⁵N₂-Labeled histamine and N^τ-[methyl-d₃]methylhistamine were used as internal standards. Histamine and N^τ-methylhistamine were converted to the derivatives N^α-heptafluorobutyryl-N^τ-ethoxycarbonylhistamine and N^α-heptafluorobutyryl-N^τ-methylhistamine, respectively. After these derivatives had been purified on a small column packed with CPG-10, the molecular ions were monitored during selected ion monitoring. Linear standard curves were obtained in the range of 0.5–10 ng/ml for both compounds. The reliability of the histamine analysis was demonstrated by using two different ion pairs, while a comparison with results from two different derivatizations on the same urine sample also established the specificity of the N^τ-methylhistamine analysis. An increase of 1 ng of histamine in the plasma could be precisely determined by the present method. The histamine content of plasma from five normal subjects was determined as 0.83 ÷ 0.37 (S.D.) ng/ml and the N^τ-methylhistamine content in most subjects was below the limits of this measurement. High excretion of histamine was noted in the urine collected in the early morning from a patient with nephritis.     

Histamine H3 Receptor-Mediated Signaling Protects Mice from Cerebral Malaria

Background

Histamine is a biogenic amine that has been shown to contribute to several pathological conditions, such as allergic conditions, experimental encephalomyelitis, and malaria. In humans, as well as in murine models of malaria, increased plasma levels of histamine are associated with severity of infection. We reported recently that histamine plays a critical role in the pathogenesis of experimental cerebral malaria (CM) in mice infected with Plasmodium berghei ANKA. Histamine exerts its biological effects through four different receptors designated H1R, H2R, H3R, and H4R.

Principal Findings

In the present work, we explored the role of histamine signaling via the histamine H3 receptor (H3R) in the pathogenesis of murine CM. We observed that the lack of H3R expression (H3R^−/− mice) accelerates the onset of CM and this was correlated with enhanced brain pathology and earlier and more pronounced loss of blood brain barrier integrity than in wild type mice. Additionally tele-methylhistamine, the major histamine metabolite in the brain, that was initially present at a higher level in the brain of H3R^−/− mice was depleted more quickly post-infection in H3R^−/− mice as compared to wild-type counterparts.

Conclusions

Our data suggest that histamine regulation through the H3R in the brain suppresses the development of CM. Thus modulating histamine signaling in the central nervous system, in combination with standard therapies, may represent a novel strategy to reduce the risk of progression to cerebral malaria.     

Activation of protein kinase in the guinea pig fundic gastric mucosa by histamine.

The effect of histamine, 1,4-methylhistamine and ethanol on cyclic AMP levels and protein kinase activation was measured in tissue strips from the fundic region of guinea pig gastric mucosa. Histamine induced a significant elevation of tissue cyclic AMP levels and also $\text{in situ}$ activation of the protein kinase. 1,4-methylhistamine, an inactive analog of histamine, and ethanol had no effect on these two parameters. Results suggest that protein kinase activation is involved in the cyclic AMP-mediated action of histamine on the gastric fundic mucosa.     

Monoamine oxidase-dependent histamine catabolism accounts for post-ischemic cardiac redox imbalance and injury

Monoamine oxidase (MAO), a mitochondrial enzyme that oxidizes biogenic amines generating hydrogen peroxide, is a major source of oxidative stress in cardiac injury. However, the molecular mechanisms underlying its overactivation in pathological conditions are still poorly characterized.Here, we investigated whether the enhanced MAO-dependent hydrogen peroxide production can be due to increased substrate availability using a metabolomic profiling method. We identified N¹-methylhistamine -the main catabolite of histamine- as an important substrate fueling MAO in Langendorff mouse hearts, directly perfused with a buffer containing hydrogen peroxide or subjected to ischemia/reperfusion protocol. Indeed, when these hearts were pretreated with the MAO inhibitor pargyline we observed N¹-methylhistamine accumulation along with reduced oxidative stress. Next, we showed that synaptic terminals are the major source of N¹-methylhistamine. Indeed, in vivo sympathectomy caused a decrease of N¹-methylhistamine levels, which was associated with a marked protection in post-ischemic reperfused hearts. As far as the mechanism is concerned, we demonstrate that exogenous histamine is transported into isolated cardiomyocytes and triggers a rise in the levels of reactive oxygen species (ROS). Once again, pargyline pretreatment induced intracellular accumulation of N¹-methylhistamine along with decrease in ROS levels. These findings uncover a receptor-independent mechanism for histamine in cardiomyocytes.In summary, our study reveals a novel and important pathophysiological causative link between MAO activation and histamine availability during pathophysiological conditions such as oxidative stress/cardiac injury.     

Regulation of Norepinephrine Release from Isolated Bovine Irides by Histamine

In the present study, we investigated the effect of histamine on sympathetic neurotransmission from isolated, superfused bovine irides. We also studied the pharmacology of prejunctional histamine receptors that regulate the release of norepinephrine (NE) from this tissue. The effect of exogenous histamine and various histamine receptor agonists was examined on the release of [³H]-norepinephrine ([³H]NE) triggered by electrical field stimulation using the Superfusion Method. Histamine receptor agonists caused a concentration-dependent inhibition of field-stimulated [³H]NE overflow with the following rank order of potency: imetit > histamine > R-α-methylhistamine. In all cases, the inhibitory action of histamine receptor agonists was attenuated at high concentrations of these compounds. The histamine receptor antagonists, clobenpropit (H₃-antagonist/H₄-agonist) and thioperamide (H₃-antagonist) blocked the inhibitory response elicited by R-α-methylhistamine and imetit, respectively. Inhibitory effects of R-α-methylhistamine and clonidine were not additive suggesting that prejunctional H₃- and α₂-adrenoceptors coexist at neurotransmitter release sites. We conclude that histamine produces an inhibitory action on sympathetic neurotransmission in the bovine iris, an effect mimicked by selective H₃-receptor agonists and blocked by H₃-antagonists.     

Analysis of N-methylhistamine by gas chromatography–mass spectrometry

A gas chromatography–electron capture mass spectrometry assay has been developed for the histamine H₃ receptor agonist, N^α-methylhistamine (N^α-MH). The assay is linear from 50 pg–10 ng, with a limit of detection of 50 pg/ml for gastric juice and plasma, and 50 pg/sample for bacteria (10⁷–10⁸ CFU) and gastric tissue (5–10 mg wet weight). The limits of quantification are 100 pg/ml for gastric juice (%RSD=1.4) and plasma (%RSD=9.4), and 100 pg/sample for bacteria (%RSD=3.9) and tissue (%RSD=5.8). N^α-MH was not present in human plasma, but low levels (1.4 ng/ml and 0.4 ng/ml) were detected in two samples of human gastric juice obtained from patients infected with Helicobacter pylori.     

Gas chromatographic—mass spectrometric assay to measure urinary N-methylhistamine excretion in man

An assay has been developed for N^τ-methylhistamine, a major metabolite of the autocoid histamine, based on gas chromatography—electron-capture negative-ion chemical ionisation mass spectrometry. N^τ-Methylhistamine was extracted from urine by cation-exchange chromatography and converted to its di-(3,5-bistrifluoromethylbenzoyl) derivative. The latter has good chromatographic properties and gives a negative-ion mass spectrum with the molecular ion (M, m/z 605) as base peak. A commercially available trideuterated analogue of N^τ-methylhistamine was used as internal standard. Basal urinary excretion of N^τ-methylhistamine in five normal subjects was found to be 0.21 ± 0.05 μmol/h (289 ± 74 μmol/mol of creatinine). This value was not significantly altered in these subjects following the infusion of a sub-pharmacological dose of histamine. In eight atopic volunteers, basal urinary excretion of N^τ-methyl-histamine was also not significantly changed following challenge with inhaled allergen.     

Histamine H<Subscript>3</Subscript> Receptor Agonists Decrease Hypothalamic Histamine Levels and Increase Stereotypical Biting in Mice Challenged with Methamphetamine

The effects of the histamine H₃ receptor agonists (R)-α-methylhistamine, imetit and immepip on methamphetamine (METH)-induced stereotypical behavior were examined in mice. The administration of METH (10 mg/kg, i.p.) to male ddY mice induced behaviors including persistent locomotion and stereotypical behaviors, which were classified into four categories: stereotypical head-bobbing (1.9%), circling (1.7%), sniffing (14.3%), and biting (82.1%). Pretreatment with (R)-α-methylhistamine (3 and 10 mg/kg, i.p.) significantly decreased stereotypical sniffing, but increased stereotypical biting induced by METH, in a dose-dependent manner. This effect of (R)-α-methylhistamine on behavior was mimicked by imetit or immepip (brain-penetrating selective histamine H₃ receptor agonists; 10 mg/kg, i.p. for each drug). Hypothalamic histamine levels 1 h after METH challenge were significantly increased in mice pretreated with saline. These increases in histamine levels were significantly decreased by pretreatment with histamine H₃ receptor agonists, effects which would appear to underlie the shift from METH-induced stereotypical sniffing to biting.     

Fluorometric determination of spermidine using o-phthalaldehyde: optimum reaction conditions and tests of identity

Spermidine and histamine react with o-phthalaldehyde at alkaline pH, giving rise to fluorescent conjugation products that are stabilized by acidification to pH 2–4. The reaction has been used in the fluorometric assay of both these compounds. In the present study, the reaction conditions have been analyzed with the purpose of improving the sensitivity as well as the specificity of the spermidine assay. The sensitivity was improved by carrying out the condensation at pH 11.0–11.6 for 2 min at 100°C. Under these conditions, the lowest measurable amount of spermidine was 10 ng/ml, and the fluorescence of histamine (below 1–2 μg/ml) was nonmeasurable. Boiling the samples for 1 hr after the acidification did not affect the spermidine fluorescence but abolished residual histamine fluorescence. The spermidine fluorescence failed to develop in the presence of CdCl₂ or SrCl₂, whereas the histamine fluorescence was unaffected. Crude extracts of rat brain gave fluorescence readings similar to those of butanol extracts, suggesting that extensive purification of tissue sperimidine prior to assay is not always necessary.     

Imidazoleacetic Acid, a γ-Aminobutyric Acid Receptor Agonist, Can Be Formed in Rat Brain by Oxidation of Histamine

Abstract: It is generally accepted that in mammalian brain histamine is metabolized solely by histamine methyltransferase (HMT), to form tele -methylhistamine, then oxidized to tele -methylimidazoleacetic acid. However, histamine's oxidative metabolite in the periphery, imidazoleacetic acid (IAA), is also present in brain and CSF, and its levels in brain increase after inhibition of HMT. To reinvestigate if brain has the capacity to oxidize histamine and form IAA, conscious rats were injected with [³H]histamine (10 ng), either into the lateral ventricles or cisterna magna, and decapitated 30 min later. In brains of saline-treated rats, most radioactivity recovered was due to tele -methylhistamine and tele -methylimidazoleacetic acid. However, significant amounts of tritiated IAA and its metabolites, IAA-ribotide and IAA-riboside, were consistently recovered. In rats pretreated with metoprine, an inhibitor of HMT, labeled IAA and its metabolites usually comprised the majority of histamine's tritiated metabolites. [³H]Histamine given intracisternally produced only trace amounts of oxidative metabolites. Formation of IAA, a potent GABA-A agonist with numerous neurochemical and behavioral effects, from minute quantities of histamine in brain indicates a need for reevaluation of histamine's metabolic pathway or pathways in brain and suggests a novel mechanism for interactions between histamine and the GABAergic system.     

CYCLIC ADENOSINE 3'',5''-MONOPHOSPHATE FORMATION IN GUINEA-PIG BRAIN SLICES: EFFECT OF H1- AND H2-HISTAMINERGIC AGONISTS

—A variety of histamine analogs elicit accumulations of radioactive cyclic AMP in guinea-pig neocortical and hippocampal slices labelled during a prior incubation with [¹⁴C]adenine. The H₁agonist, 2-aminoethylthiazole, elicits accumulation of cyclic AMP in neocortical and hippocampal slices both in the absence or presence of adenosine. The presence of adenosine increases the maximum response to 2-aminoethylthiazole and decreases the EC₅₀ by nearly 10-fold. In the absence of adenosine the effects of 2-aminoethylthiazole are antagonized in hippocampal slices by both d-brompheniramine and metiamide, while in the presence of adenosine only d-brompheniramine is an effective antagonist. The H₂-agonist, 4-methylhistamine, elicits a somewhat smaller accumulation of cyclic AMP than does 2-aminoethylthiazole in both cortical and hippocampal slices. In the presence of adenosine the response to 4-methylhistamine is enhanced, but is markedly lower than that seen with the combination of adenosine and 2-aminoethylthiazole. The dose-response relationship for 4-methylhistamine in the presence of adenosine appears in hippocampal slices to consist of two components. The response to 4-methylhistamine in the absence of adenosine is blocked by metiamide, while in the presence of adenosine the response is partially blocked by both H₁ and H₂-antagonists. The accumulation of cyclic AMP elicited by histamine is greatly increased by adenosine but the EC₅₀ is not significantly decreased. The results suggest that (i) both H₁- and H₂-receptors regulate cyclic AMP-formation in the central nervous system, (ii) the synergism between adenosine and histamine is mediated primarily by interaction with H₁-receptors and (iii) that adenosine greatly increases the affinity of the H₁-receptors for both H₁ and H₂-agonists without affecting its affinity for histamine.     

Existence of carcinine, a histamine-related compound, in mammalian tissues

Carcinine (beta-alanylhistamine) was synthesized in vitro from histamine and beta-alanine. It was detected quantitatively using an HPLC method previously described for the quantification of the related compounds histamine, histidine, carnosine and 3-methylhistamine. Carcinine was identified in several tissue of the rat, guinea pig, mouse and human, and was then shown to be metabolically related in vivo to histamine, histidine, carnosine and 3-methylhistamine through radioisotopic labeling. The results demonstrate that carcinine may be concurrently quantitated using the same HPLC method as that used to measure histamine, histidine, carnosine and 3-methylhistamine. These findings suggest a role for carcinine in the carnosine-histidine-histamine metabolic pathway and in the mammalian physiologic response to stress.     

Histamine signalling in Schistosoma mansoni: Immunolocalisation and characterisation of a new histamine-responsive receptor (SmGPR-2)

In parasitic platyhelminthes, including Schistosoma mansoni, biogenic amines play several important roles in the control of motility, metabolism and reproduction. A bioinformatics analysis of the S. mansoni genome identified approximately 16 full-length G protein-coupled receptors (GPCRs) that share significant homology with aminergic receptors from other species. Six of these sequences are structurally related to SmGPR-1 (formerly SmGPCR), a previously described histamine receptor of S. mansoni, and constitute a new clade of amine-like GPCRs. Here we report the cloning of a second member of this clade, named SmGPR-2. The full-length receptor cDNA was expressed in Saccharomyces cerevisiae and shown to be activated by histamine and 1-methylhistamine, whereas other common biogenic amines had no significant effect. Antagonist assays showed that SmGPR-2 was inhibited by classical biogenic amine antagonists but the pharmacological profile was unlike those of known mammalian histamine receptors. Confocal immunolocalisation studies revealed that SmGPR-2 was expressed in the nervous system and was particularly enriched in the subtegumental neuronal plexus of adult S. mansoni and larvae. The ligand, histamine, was found to be widely distributed, mainly in the peripheral nervous system including the subtegumental plexus where the receptor is also expressed. Finally, SmGPR-2 was shown to be developmentally regulated at the RNA level. Quantitative PCR studies showed it was up-regulated in the parasitic stages compared with cercaria and expressed at the highest level in young schistosomula. The widespread distribution of histamine and the presence of at least two receptors in S. mansoni suggest that this transmitter is an important neuroactive substance in schistosomes.     

Rapid onset of (R)-α-methylhistamine protection in response to ethanol-induced histologic damage in rat gastric mucosa

The influence of pretreatment with (R)-α-methylhistamine, selective agonist of histamine H₃ receptors, has been investigated on gastric mucosal lesions at different time intervals, from 5 to 60 minutes, after administration of absolute ethanol in the rat. The amount and depth of lesions were quantitatively evaluated by light microscopy. In rats pretreated with (R)-α-methylhistamine, the integrity of the mucosa was preserved in approximately 80% of the total mucosal length measured despite ethanol challenge. Prevention of lesion formation was as great at 5 min after ethanol administration as at 60 min. When present, damage involved mainly superficial mucosa and lesions extending deeply into the gland region were evident in 1–2.5% of the total mucosa. Present findings indicate that mechanisms by which (R)-α-methylhistamine operates enable the mucosa to counteract damage just from the moment of exposure to ethanol and that protection is exerted both on surface and pit cells and on gastric glands.     

Presence and distribution of histaminergic components in rat and bovine retina

The presence of histamine and its related enzymes, histidine decarboxylase and histamine N-methyltransferase and the subcellular distribution of the amine and of H₁-receptors were studied in the retina of two mammalian species. Histamine is present in rat and bovine retinas in concentrations (113 ± 10 and 72 ± 9 ng/g wet tissue, respectively) similar to those found in the brain. Histological examination and release experiments with Compound 48/80 performed in rat retina indicate a non mast cell location for the amine. Histidine decarboxylase and histamine N-methyltransferase activities in rat and bovine retinas were also comparable to those found in brain cortex suggesting that histamine can be synthesized and catabolyzed in situ. Subcellular fractionation of bovine retina showed that both the amine and H₁-receptors are concentrated in particulate fractions where small sized synaptosomes sediment, presumably derived from horizontal and amacrine cells. These results are in agreement with a neurotransmitter or neuromodulator role for histamine in cells of the retinal inner nuclear layer.     

Role of histamine receptors in the effects of histamine on the production of reactive oxygen species by whole blood phagocytes

Aims

The diverse physiological functions of histamine are mediated through distinct histamine receptors. In this study we investigated the role of H₂R and H₄R in the effects of histamine on the production of reactive oxygen species by phagocytes in whole blood.

Main methods

Changes in reactive oxygen species (ROS) production by whole blood phagocytes after treatment with histamine, H₄R agonists (4-methylhistamine, VUF8430), H₂R agonist (dimaprit) and their combinations with H₄R antagonist (JNJ10191584) and H₂R antagonist (ranitidine) were determined using the chemiluminescence (CL) assay. To exclude the direct scavenging effects of the studied compounds on the CL response, the antioxidant properties of all compounds were measured using several methods (TRAP, ORAC, and luminol–HRP–H₂O₂ based CL).

Key findings

Histamine, 4-methylhistamine, VUF8430 and dimaprit inhibited the spontaneous and OZP-activated whole blood CL in a dose-dependent manner. On the other hand, only VUF8430 was able to inhibit PMA-activated whole blood CL. Ranitidine, but not JNJ10191584, completely reduced the effects of histamine, 4-methylhistamine and dimaprit. The direct scavenging ability of tested compounds was negligible.

Significance

Our results demonstrate that the inhibitory effects of histamine on ROS production in whole blood phagocytes were caused by H₂R. Our results also suggest that H₄R agonists in concentrations higher than 10^− 6 M may also influence ROS production via binding to H₂R.     

Histamine stimulates human lung fibroblast migration

Histamine is a potent mediator in allergic inflammatory processes and is released by basophils and mast cells. The aim of this study was to investigate the effect of histamine on in vitro migration of human fetal lung fibroblasts (HFL-1) to human plasma fibronectin (HFn), a chemoattractant. Using the blindwell chamber technique, histamine alone had no chemotactic activity. However, histamine augmented HFn-induced HFL-1 migration at concentrations ranging between 0 and 10^?7 M (290.6 ± 20.8%) (P < 0.05). The concentration-response was bell-shaped. The effect of histamine increased with time. The stimulatory effect of histamine on HFL-1 migration was inhibited by an H4 receptor antagonist, JNJ7777120 (10^?5 M). Histamine’s effect was also inhibited by pertussis toxin (50 ng/ml), showing that the effect was mediated by the H4 receptor. This study demonstrated that histamine has the potential to stimulate human lung fibroblast migration, and thus may contribute to regulation of wound healing and the development of fibrotic disorders of the lung.     

Uptake of histamine by mouse peritoneal macrophages and a macrophage cell line,RAW264.7

We have previously demonstrated that dietary histamine is accumulated in the spleens of L-histidine decarboxylase (HDC)-deficient mice, which lack endogenous histamine synthesis. To characterize the clearance system for dietary histamine in mice, we investigated the cell type and mechanism responsible for histamine uptake in the spleens of HDC-deficient mice. Immunohistochemical analyses using an antihistamine antibody indicated that a portion of the CD14⁺ cells in the spleen is involved in histamine storage. Peritoneal macrophages obtained from Balb/c mice and a mouse macrophage cell line, RAW264.7, had potential for histamine uptake, which was characterized by a low affinity and high capacity for histamine. The histamine uptake by RAW264.7 cells was observed at physiological temperature and was potently inhibited by pyrilamine, chlorpromazine, quinidine, and chloroquine, moderately inhibited by N-methylhistamine, dopamine, and serotonin, and not affected by tetraethylammonium and 1-methyl-4-phenylpyridinium. Intracellular histamine was not metabolized in RAW264.7 cells and was released at physiological temperature in the absence of extracellular histamine. These results suggest that histamine uptake by macrophages may be involved in the clearance of histamine in the local histamine-enriched environment. cation transporter; chlorpromazine; pyrilamine; quinidine