Patho-Pharmacological Research of Anti-allergic Natural Products Targeting Antihistamine-Sensitive and -Insensitive Allergic Mechanisms.

Histamine H1 receptor (H1R) has a special up-regulation mechanism by the stimulation of H1R, mediated by protein kinase C-delta (PKCδ) signaling and H1R gene expression, resulting increase in H1R signaling. Increase in H1R mRNA in nasal mucosa was induced after the provocation of nasal hypersensitivity model rats and suppressed by the pre-treatment of antihistamines. Improvement of nasal symptoms and suppression of H1R mRNA expression in nasal mucosa were also observed by the pre-treatment of antihistamines in pollinosis patients. Elucidation of a correlation between symptoms and H1R mRNA level suggests that H1R gene is an allergic disease (AD)-susceptibility gene, targeted by antihistamines. Similar to antihistamines, pre-treatment of Kujin extract, an anti-allergic Kampo medicine improved nasal symptoms and suppressed H1R mRNA expression in nasal hypersensitivity model rats. (-)-Maackiain targeting heat shock protein 90 (Hsp90) was isolated as an inhibitor of PKCδ signaling-mediated H1R gene expression from Kujin extract. In addition to H1R-mediated activation of H1R gene expression as the first mechanism, nuclear factor of activated T-cells (NFAT)-mediated IL-9 gene expression is suggested to participate to allergic symptoms as the second mechanism insensitive to antihistamines. Pyrogallol and proanthocyanidin suppressing IL-9 gene expression were discovered from Awa-tea and lotus root knots, respectively. Combination therapy using medicines suppressing both H1R gene expression and IL-9 gene expression is promising for outstanding alleviation of AD. Multifactorial diseases involving H1R gene expression may be treated by the combination therapy with antihistamine and complementary drugs, and diseases involving PKCδ signaling may be treated by drugs targeting Hsp90.

Effects of narrow-band UVB on nasal symptom and upregulation of histamine H1 receptor mRNA in allergic rhinitis model rats.

BACKGROUND: Phototherapy with narrow-band ultraviolet B (narrow-band UVB) is clinically effective treatment for atopic dermatitis. In the present study, we examined the effects of intranasal irradiation with narrow-band UVB on nasal symptom, upregulation of histamine H1 receptor (H1R) gene expression and induction of DNA damage in the nasal mucosa of allergic rhinitis (AR) model rat. METHODS: AR model rats were intranasally irradiated with 310 nm of narrow-band UVB. Nasal mucosal levels of H1R mRNA were measured using real-time quantitative reverse transcriptase (RT)-PCR. DNA damage was evaluated using cyclobutane pyrimidine dimer (CPD) immunostaining. RESULTS: In toluene 2,4-diisocyanate (TDI)-sensitized rats, TDI provoked sneezes and H1R gene expression in the nasal mucosa. Intranasal pre-irradiation with 310 nm narrow-band UVB at doses of 600 and 1400, but not 200 mJ/cm2 significantly inhibited the number of sneezes and upregulation of H1R gene expression provoked by TDI. CPD-positive cells appeared in the nasal mucosa after intranasal narrow-band UVB irradiation at a dose of 1400, but not 200 and 600 mJ/cm2. The suppression of TDI-provoked sneezes and upregulation of H1R gene expression lasted 24 hours, but not 48 hours, after narrow-band UVB irradiation with a dose of 600 mJ/cm2. CONCLUSIONS: Intranasal pre-irradiation with narrow-band UVB dose-dependently inhibited sneezes and upregulation of H1R gene expression of the nasal mucosa in AR model rats, suggesting that the inhibition of nasal upregulation of H1R gene expression suppressed nasal symptom. The suppression after narrow-band UVB irradiation at a dose of 600 mJ/cm2 was reversible without induction of DNA damage. These findings indicated that low-dose narrow-band UVB phototherapy could be effectively and safely used for AR treatment in a clinical setting. LEVEL OF EVIDENCE: NA.

Identification of pyrogallol from Awa-tea as an anti-allergic compound that suppresses nasal symptoms and IL-9 gene expression.

As the expression level of allergic disease sensitive genes are correlated with the severity of allergic symptoms, suppression of these gene expressions could be promising therapeutics. We demonstrated that protein kinase Cδ / heat shock protein 90-mediated H1R gene expression signaling and nuclear factor of activated T-cells (NFAT)-mediated IL-9 gene expression signaling are responsible for the pathogenesis of pollinosis. Treatment with Awa-tea combined with wild grape hot water extract suppressed these signaling and alleviated nasal symptoms in toluene-2,4-diisocyanate (TDI)-sensitized rats. However, the underlying mechanism of its anti-allergic activity is not elucidated yet. Here, we sought to identify an anti-allergic compound from Awa-tea and pyrogallol was identified as an active compound. Pyrogallol strongly suppressed ionomycin-induced up-regulation of IL-9 gene expression in RBL-2H3 cells. Treatment with pyrogallol in combination with epinastine alleviated nasal symptoms and suppressed up-regulation of IL-9 gene expression in TDI-sensitized rats. Pyrogallol itself did not inhibit calcineurin phosphatase activity. However, pyrogallol suppressed ionomycin-induced dephosphorylation and nuclear translocation of NFAT. These data suggest pyrogallol is an anti-allergic compound in Awa-tea and it suppressed NFAT-mediated IL-9 gene expression through the inhibition of dephosphorylation of NFAT. This might be the underlying mechanism of the therapeutic effects of combined therapy of pyrogallol with antihistamine. J. Med. Invest. 67 : 289-297, August, 2020.

Olanzapine increases AMPK-NPY orexigenic signaling by disrupting H1R-GHSR1a interaction in the hypothalamic neurons of mice.

Second generation antipsychotics, particularly olanzapine, induce severe obesity, which is associated with their antagonistic effect on the histamine H1 receptor (H1R). We have previously demonstrated that oral administration of olanzapine increases the concentration of neuropeptide Y (NPY) in the hypothalamus of rats, accompanied by hyperphagia and weight gain. However, it is unclear if the increased NPY after olanzapine administration is due to its direct effect on hypothalamic neurons and its H1R antagonistic property. In the present study, we showed that with an inverted U-shape dose-response curve, olanzapine increased NPY expression in the NPY-GFP hypothalamic neurons; however, this was not the case in the hypothalamic neurons of H1R knockout mice. Olanzapine inhibited the interaction of H1R and GHSR1a (ghrelin receptor) in the primary mouse hypothalamic neurons and NPY-GFP neurons examined by confocal fluorescence resonance energy transfer (FRET) technology. Furthermore, an H1R agonist, FMPH inhibited olanzapine activation of GHSR1a downstream signaling pAMPK and transcription factors of NPY (pFOXO1 and pCREB) in the hypothalamic NPY-GFP cell. However, an olanzapine analogue (E-Olan) with lower affinity to H1R presented negligible enhancement of pCREB within the nucleus of NPY neurons. These findings suggest that the H1R antagonist property of olanzapine inhibits the interaction of H1R and GHSR1a, activates GHSR1a downstream signaling pAMPK-FOXO1/pCREB and increases hypothalamic NPY: this could be one of the important molecular mechanisms of H1R antagonism of olanzapine-induced obesity in antipsychotic management of psychiatric disorders.

Ameliorative Effect of Hesperidin Against Motion Sickness by Modulating Histamine and Histamine H1 Receptor Expression.

Motion sickness (MS) is the visceral discomfort caused due to contradicting visual and vestibular inputs to the brain leading to nausea and vomiting. Sensory conflict theory which proves histamine elevations as the primary reason for MS provides a path for an effective pharmaco-therapy. We aimed to evaluate the anti-MS effect of hesperidin (HSP) by modulating histamine and histamine receptor H1 (HRH1) expression. The inhibitory effect of HSP on histamine release was studied in KU812 cells treated with 10 µM calcium ionophore. The in vivo anti-MS effect of HSP was evaluated in Balb/c mice. Thirty six mice were divided into six groups namely, normal control (NC, no rotation), hesperidin at 80 mg/kg body weight control (HSP80, no rotation), motion sickness (MS, rotation induced), dimenhydrinate (Standard drug) at 20 mg/kg body weight + rotation (STD + MS), hesperidin at 40 mg/kg body weight + rotation (HSP40 + MS) and hesperidin at 80 mg/kg body weight + rotation (HSP80 + MS). Hypothalamus and brainstem samples were analysed for histamine levels and HRH1 expression by RT-PCR, Western blot and immunohistochemistry analysis. Calcium ionophore treated KU812 cells significantly increased histamine release when compared to control cells. Pre-treatment with HSP inhibited histamine, HRH1 mRNA and protein expression. Histamine, HRH1 mRNA and protein expression in hypothalamus and brainstem samples of MS group increased significantly when compared to the NC group. Pre-treatment with HSP significantly reduced histamine, HRH1 mRNA and protein expression. Thus, indicating that HSP has a potent anti- MS effect by decreasing the elevated levels of histamine, HRH1 mRNA and protein expression in hypothalamus and brainstem regions.

The Relaxant Effect of Plantago Major on Rat Tracheal Smooth Muscles and Its Possible Mechanisms.

This study was conducted to evaluate the possible mechanisms of the relaxant effects of hydroalcoholic extract of Plantago major (P. major) on tracheal smooth muscle (TSM) in rats. The effects of cumulative concentrations of P. major (5, 10, 20 and 40 mg/mL) and theophylline (0.2, 0.4, 0.6 and 0.8 mM) were evaluated on pre-contracted TSM with 10 µΜ methacholine or 60 mM KCl. To determine the possible mechanisms, the relaxant effect of the plant was also examined on incubated TSM with atropine, indomethacin, chlorpheniramine, glibenclamide, diltiazem, papaverine, and propranolol. The results indicated concentration-dependent relaxant effects for P. major in non-incubated TSM contracted by methacholine or KCl. There was no statistically significant difference in the relaxant effects of P. major between non-incubated and incubated tissues with indomethacin, papaverine, and propranolol. However, the relaxant effects of P. major in incubated tissues with atropine (p<0.01 to p<0.001), chlorpheniramine (p<0.05 to p<0.001), glibenclamide (p<0.05), or diltiazem (p<0.01) were significantly lower than non-incubated TSM. P. major indicated relatively potent relaxant effects which were lower than those of theophylline. Muscarinic and histamine (H1) receptors inhibition, as well as calcium channel blocking and potassium channel opening effects are suggested to contribute to the TSM relaxant effect of the plant.

Effects of loratadine, a histamine H1 receptor antagonist, on the skeletal system of young male rats.

BACKGROUND: Histamine H1 receptor antagonists are widely used in the treatment of allergic diseases. H1 receptors are expressed on bone cells and histamine takes part in regulation of bone metabolism. Loratadine is often prescribed to children. PURPOSE: The aim of the present study was to investigate the effects of loratadine on the skeletal system of young rats. MATERIAL AND METHODS: Loratadine (0.5, 5, and 50 mg/kg p.o. daily) was administered for 4 weeks to male Wistar rats, 6-week-old at the start of the experiment. Bone mass, mass of bone mineral, calcium, and phosphorus content in the bone mineral of the tibia, femur, and L-4 vertebra, histomorphometric parameters of the femur, mechanical properties of the proximal tibial metaphysis, femoral diaphysis and femoral neck, and serum levels of bone turnover markers were examined. RESULTS: Loratadine at 0.5 and 5 mg/kg did not significantly affect the skeletal system of young rats. At 50 mg/kg, loratadine decreased the femoral length, increased content of calcium and phosphorus in the bone mineral of the vertebra, and tended to improve mechanical properties of the tibial metaphysis. CONCLUSION: High-dose loratadine slightly but significantly affected development of the skeletal system in rapidly growing rats.

Effects of irradiation with narrowband-ultraviolet B on up-regulation of histamine H1 receptor mRNA and induction of apoptosis in HeLa cells and nasal mucosa of rats.

Narrowband-ultraviolet B (NB-UVB) phototherapy is used for the treatment of atopic dermatitis. Previously, we reported that irradiation with 200 mJ/cm2 of 310 nm NB-UVB suppressed phorbol-12-myristate-13-acetate (PMA)-induced up-regulation of histamine H1 receptor (H1R) gene expression without induction of apoptosis in HeLa cells. However, the effect of NB-UVB irradiation on nasal symptoms is still unclear. Here, we show that low dose irradiation with 310 nm NB-UVB alleviates nasal symptoms in toluene 2,4-diisocyanate (TDI)-sensitized allergy model rats. Irradiation with 310 nm NB-UVB suppressed PMA-induced H1R mRNA up-regulation in HeLa cells dose-dependently at doses of 75-200 mJ/cm2 and reversibly at a dose of 150 mJ/cm2 without induction of apoptosis. While, at doses of more than 200 mJ/cm2, irradiation with 310 nm NB-UVB induced apoptosis. Western blot analysis showed that the suppressive effect of NB-UVB irradiation on H1R gene expression was through the inhibition of ERK phosphorylation. In TDI-sensitized rat, intranasal irradiation with 310 nm NB-UVB at an estimated dose of 100 mJ/cm2 once a day for three days suppressed TDI-induced sneezes and up-regulation of H1R mRNA in nasal mucosa without induction of apoptosis. These findings suggest that repeated intranasal irradiation with low dose of NB-UVB could be clinically used as phototherapy of AR.

Effect of wild grape on the signaling of histamine H1 receptor gene expression responsible for the pathogenesis of allergic rhinitis.

As expression level of allergic disease-sensitive genes are correlated with allergic symptom severity, suppression of these gene expressions could be good therapeutics. We have demonstrated that PKCδ signaling and NFAT signaling, involve in histamine H1 receptor (H1R) and IL-9 gene expressions, respectively, are responsible for the pathogenesis of allergic rhinitis. We explore anti-allergic compounds that suppress these signaling pathways and found that wild grape (WG) contains such compounds. Here, we investigated the effect of WG hot water extract (WGE) on the signaling pathways for PKCδ-mediated H1R and NFAT-mediated IL-9 gene expressions. WGE suppressed histamine/PMA-induced H1R gene up-regulation in HeLa cells. Toluene-2,4-diisocyanate (TDI)-induced H1R mRNA elevation in TDI-sensitized rats was also suppressed by WGE treatment. Treatment with WGE in combination with Awa-tea, suppresses NFAT signaling-mediated IL-9 gene, markedly alleviated nasal symptoms. Furthermore, WGE suppressed PMA-induced IL-33 gene up-regulation in Swiss 3T3 cells. Data suggest that combination of WGE, suppresses PKCδ signaling with Awa-tea, suppresses NFAT signaling would have distinct clinical and therapeutic advantages as a substitute for anti-allergic drugs. In addition, as the expression level of IL-33 mRNA was correlated with the blood eosinophils number in patients with pollinosis, WG could alleviate eosinophilic inflammation through the suppression of IL-33 gene expression. J. Med. Invest. 65:242-250, August, 2018.

A History of Drug Discovery for Treatment of Nausea and Vomiting and the Implications for Future Research.

The origins of the major classes of current anti-emetics are examined. Serendipity is a recurrent theme in discovery of their anti-emetic properties and repurposing from one indication to another is a continuing trend. Notably, the discoveries have occurred against a background of company mergers and changing anti-emetic requirements. Major drug classes include: (i) Muscarinic receptor antagonists-originated from historical accounts of plant extracts containing atropine and hyoscine with development stimulated by the need to prevent sea-sickness among soldiers during beach landings; (ii) Histamine receptor antagonists-searching for replacements for the anti-malaria drug quinine, in short supply because of wartime shipping blockade, facilitated the discovery of histamine (H1) antagonists (e.g., dimenhydrinate), followed by serendipitous discovery of anti-emetic activity against motion sickness in a patient undergoing treatment for urticaria; (iii) Phenothiazines and dopamine receptor antagonists-investigations of their pharmacology as "sedatives" (e.g., chlorpromazine) implicated dopamine receptors in emesis, leading to development of selective dopamine (D2) receptor antagonists (e.g., domperidone with poor ability to penetrate the blood-brain barrier) as anti-emetics in chemotherapy and surgery; (iv) Metoclopramide and selective 5-hydroxytryptamine3(5-HT3) receptor antagonists-metoclopramide was initially assumed to act only via D2 receptor antagonism but subsequently its gastric motility stimulant effect (proposed to contribute to the anti-emetic action) was shown to be due to 5-hydroxytryptamine4 receptor agonism. Pre-clinical studies showed that anti-emetic efficacy against the newly-introduced, highly emetic, chemotherapeutic agent cisplatin was due to antagonism at 5-HT3 receptors. The latter led to identification of selective 5-HT3 receptor antagonists (e.g., granisetron), a major breakthrough in treatment of chemotherapy-induced emesis; (v) Neurokinin1receptor antagonists-antagonists of the actions of substance P were developed as analgesics but pre-clinical studies identified broad-spectrum anti-emetic effects; clinical studies showed particular efficacy in the delayed phase of chemotherapy-induced emesis. Finally, the repurposing of different drugs for treatment of nausea and vomiting is examined, particularly during palliative care, and also the challenges in identifying novel anti-emetic drugs, particularly for treatment of nausea as compared to vomiting. We consider the lessons from the past for the future and ask why there has not been a major breakthrough in the last 20 years.

[Acupoint Injection at "Yingxiang"(LI 20) and "Yintang"(GV 29) May Relieve Nasal Allergic Symptoms Possibly by Down-regulating Expression of Histamine Receptor H 1 and H 4 in Nasal Mucosa of Allergic Rhinitis Rats].

OBJECTIVE: To observe the effect of acupoint injection at "Yingxiang"(LI 20) and "Yintang"(GV 29) on nasal allergic reactions and the expression of histamine receptor H 1 and H 4 in nasal mucosa of allergic rhinitis (AR) rats, so as to reveal its mechanism underlying improvement of AR. METHODS: SD rats were randomized into normal, model, non-acupoint injection and acupoint injection groups (n=8 in each). The AR model was established by intraperitoneal (i.p.) injection of mixture of ovalbumin, aluminium hydroxide gel and normal saline (once every other day, for 7 times), and nasal drip of ovalbumin (on the following day of i.p.for 7 days). The mixture solution of lidocaine, dexamethasone (DXM) and transfer factor (0.1 mL/acupoint or non-acupoint) was injected into bilateral LI 20 and GV 29 in the acupoint injection group, or into the non-acupoints (about 5 cm below the armpit on both sides, and the middle point between the left "Houhai"[GV 1] and "Huantiao"[GB 30]), on the 1st , 5th, 9th, and 13th day after modeling. Symptoms of sneezing, nasal discharge, nose-rubbing, etc. were scored after the treatment. The expression levels of H1 R and H4 R proteins and genes in the nasal mucosa tissue were determined using immunohistochemistry and quantitative real-time PCR, respectively. RESULTS: Compared with the normal group, the symptom score and the expression levels of H1 R, H4 R proteins and genes in nasal mucosa were significantly increased in the model group (P<0.05). After acupoint injection for 4 times, the symptom score and the expression levels of H1 R, H4 R proteins and mRNAs were significantly down-regulated in the acupoint injection group relevant to the model group (P<0.05). There were no significant differences between the non-acupoint and the model groups in the abovementioned indexes (P>0.05), suggesting a specificity of the effect of acupoint injection. CONCLUSION: Acupoint injection can relieve the allergic symptoms of AR rats, which may be related to its effects in down-regulating the over expression of H1 R and H4 R proteins and genes in the nasal mucosa.

Time-dependent effects of olanzapine treatment on the expression of histidine decarboxylase, H1 and H3 receptor in the rat brain: The roles in olanzapine-induced obesity.

Antipsychotic treatment, particularly olanzapine and clozapine, induces severe obesity. The Histamine H1 receptor is considered to be an important contributor to olanzapine-induced obesity, however how olanzapine modulates the histaminergic system is not sufficiently understood. This study examined the effect of olanzapine on key molecules of the histaminergic system, including histidine decarboxylase (HDC), H1 receptor (H1R) and H3 receptor (H3R), in the brain at different stages of olanzapine-induced obesity. During short-term treatment (8-day), olanzapine increased hypothalamic HDC mRNA expression and H1R binding in the arcuate nucleus (Arc) and ventromedial hypothalamus (VMH), without changing H3R binding density. HDC mRNA and Arc H1R binding were positively correlated with increased food intake, feeding efficiency and weight gain. When the treatment was extended to 16 and 36 days, H1R binding was increased not only in the hypothalamic Arc and VMH but also in the brainstem dorsal vagal complex (DVC). The H1R bindings in the Arc, VMH and DVC were positively correlated with weight gain induced by olanzapine treatment. However, the expression of HDC and H3R mRNA was not increased. These results suggest that olanzapine time-dependently modulates histamine neurotransmission, which suggested the different neuronal mechanisms underlying different stages of weight gain development. Treatment targeting the H1R may be effective for both short- and long-term olanzapine-induced weight gain.

A novel neurological function of rice bran: a standardized rice bran supplement promotes non-rapid eye movement sleep in mice through histamine H1 receptors.

SCOPE: Although rice bran has been shown to be associated with a wide spectrum of health benefits, to date, there are no reports on its effects on sleep. We investigated the effect of rice bran on sleep and the mechanism underlying this effect. METHODS AND RESULTS: Electroencephalography was used to evaluate the effects of standardized rice bran supplement (RBS) and doxepin hydrochloride (DH), a histamine H1 receptor (H1 R) antagonist used as a positive control, on sleep in mice. The mechanism of RBS action was investigated using knockout (KO) mice and ex vivo electrophysiological recordings. Oral administration of RBS and DH significantly decreased sleep latency and increased the amount of non-rapid eye movement sleep (NREMS) in mice. Similar to DH, RBS fully inhibited H1 R agonist-induced increase in action potential frequency in tuberomammillary nucleus neurons. In H1 R KO mice, neither RBS nor DH administration led to the increase in NREMS and decrease in sleep latency observed in WT mice. These results indicate that the sleep-promoting effect of RBS is completely dependent on H1 R antagonism. CONCLUSIONS: RBS decreases sleep latency and promotes NREMS through the inhibition of H1 R, suggesting that it could be a promising therapeutic agent for insomnia.

Label-free versus conventional cellular assays: Functional investigations on the human histamine H1 receptor.

A set of histamine H1 receptor (H1R) agonists and antagonists was characterized in functional assays, using dynamic mass redistribution (DMR), electric cell-substrate impedance sensing (ECIS) and various signaling pathway specific readouts (Fura-2 and aequorin calcium assays, arrestin recruitment (luciferase fragment complementation) assay, luciferase gene reporter assay). Data were gained from genetically engineered HEK293T cells and compared with reference data from GTPase assays and radioligand binding. Histamine and the other H1R agonists gave different assay-related pEC50 values, however, the order of potency was maintained. In the luciferase fragment complementation assay, the H1R preferred ß-arrestin2 over ß-arrestin1. The calcium and the impedimetric assay depended on Gq coupling of the H1R, as demonstrated by complete inhibition of the histamine-induced signals in the presence of the Gq inhibitor FR900359 (UBO-QIC). Whereas partial inhibition by FR900359 was observed in DMR and the gene reporter assay, pertussis toxin substantially decreased the response in DMR, but increased the luciferase signal, reflecting the contribution of both, Gq and Gi, to signaling in these assays. For antagonists, the results from DMR were essentially compatible with those from conventional readouts, whereas the impedance-based data revealed a trend towards higher pKb values. ECIS and calcium assays apparently only reflect Gq signaling, whereas DMR and gene reporter assays appear to integrate both, Gq and Gi mediated signaling. The results confirm the value of the label-free methods, DMR and ECIS, for the characterization of H1R ligands. Both noninvasive techniques are complementary to each other, but cannot fully replace reductionist signaling pathway focused assays.

AVN-101: A Multi-Target Drug Candidate for the Treatment of CNS Disorders.

Lack of efficacy of many new highly selective and specific drug candidates in treating diseases with poorly understood or complex etiology, as are many of central nervous system (CNS) diseases, encouraged an idea of developing multi-modal (multi-targeted) drugs. In this manuscript, we describe molecular pharmacology, in vitro ADME, pharmacokinetics in animals and humans (part of the Phase I clinical studies), bio-distribution, bioavailability, in vivo efficacy, and safety profile of the multimodal drug candidate, AVN-101. We have carried out development of a next generation drug candidate with a multi-targeted mechanism of action, to treat CNS disorders. AVN-101 is a very potent 5-HT7 receptor antagonist (Ki = 153 pM), with slightly lesser potency toward 5-HT6, 5-HT2A, and 5HT-2C receptors (Ki = 1.2-2.0 nM). AVN-101 also exhibits a rather high affinity toward histamine H1 (Ki = 0.58 nM) and adrenergic α2A, α2B, and α2C (Ki = 0.41-3.6 nM) receptors. AVN-101 shows a good oral bioavailability and facilitated brain-blood barrier permeability, low toxicity, and reasonable efficacy in animal models of CNS diseases. The Phase I clinical study indicates the AVN-101 to be well tolerated when taken orally at doses of up to 20 mg daily. It does not dramatically influence plasma and urine biochemistry, nor does it prolong QT ECG interval, thus indicating low safety concerns. The primary therapeutic area for AVN-101 to be tested in clinical trials would be Alzheimer's disease. However, due to its anxiolytic and anti-depressive activities, there is a strong rational for it to also be studied in such diseases as general anxiety disorders, depression, schizophrenia, and multiple sclerosis.

Irradiation with narrowband-ultraviolet B suppresses phorbol ester-induced up-regulation of H1 receptor mRNA in HeLa cells.

Conclusion These findings suggest that low dose irradiation with 310 nm NB-UVB specifically suppressed the up-regulation of H1R gene expression without inducing apoptosis and that UVB of shorter or longer wavelength than 310 nm NB-UVB had no such effects. Objective To develop a narrowband-ultraviolet B(NB-UVB) phototherapy for allergic rhinitis, this study investigated the effects of irradiation with NB-UVB at wavelength of 310 nm on phorbol-12-myristate-13-acetate (PMA)-induced up-regulation of histamine H1 receptor (H1R) mRNA in HeLa cells. Methods The mRNA levels of H1R in HeLa cells were measured using real-time RT-PCR. Apoptosis were evaluated with DNA fragmentation assay. Results PMA induced a significant increase in H1R mRNA expression in HeLa cells. Irradiation with 305 nm UVB and 310 nm NB-UVB, but not with 315 nm UVB at doses of 200 and 300 mJ/cm(2) significantly suppressed PMA-induced up-regulation of H1R mRNA. At a dose of 200 mJ/cm(2), irradiation with 305 nm UVB, but not with 310 nm NB-UVB, induced apoptosis, although exposure of the cells to both 305 and 310 nm UVB induced apoptosis at a dose of 300 mJ/cm(2) after PMA treatment in HeLa cells. Conversely, irradiation with 315 nm UVB at doses of 200 and 300 mJ/cm(2) did not induce apoptosis.

Effects of antihistamine on up-regulation of histamine H1 receptor mRNA in the nasal mucosa of patients with pollinosis induced by controlled cedar pollen challenge in an environmental exposure unit.

In the present study, we examined the effects of antihistamine on the up-regulation of H1R mRNA in the nasal mucosa of patients with pollinosis induced by controlled exposure to pollen using an environmental exposure unit. Out of 20 patients, we designated 14 responders, whose levels of H1R mRNA in the nasal mucosa were increased after the first pollen exposure and excluded 6 non-responders. Accordingly, the first exposure to pollen without treatment significantly induced both nasal symptoms and the up-regulation of H1R mRNA in the nasal mucosa of the responders. Subsequently, prophylactic administration of antihistamine prior to the second pollen exposure significantly inhibited both of the above effects in the responders. Moreover, the nasal expression of H1R mRNA before the second pollen exposure in the responders pretreated with antihistamine was significantly decreased, as compared with that before the first pollen exposure without treatment. These findings suggest that antihistamines suppressed histamine-induced transcriptional activation of H1R gene in the nasal mucosa, in addition to their blocking effect against histamine on H1R, resulting in a decrease of nasal symptoms. These findings further suggest that by their inverse agonistic activity, antihistamines suppress the basal transcription of nasal H1R in the absence of histamine in responders.

Histamine H1 receptor cell membrane chromatography online high-performance liquid chromatography with mass spectrometry method reveals houttuyfonate as an activator of the histamine H1 receptor.

Allergy is an abnormal reaction of the body to an allergen. Histamine is responsible for many of the acute symptoms of allergic diseases. Many of the allergic and inflammatory actions of histamine are mediated by the histamine H1 receptor. In the present study, we established a two-dimensional histamine H1 receptor/cell membrane chromatography with online high-performance liquid chromatography and mass spectrometry method for screening potential histamine-activating components in a traditional Chinese medicine injection. The specification of the method was validated by screening, separating, and identifying a mixed standard solution of diphenhydramine hydrochloride, gefitinib, tamsulosin, and nitrendipine. The Yujin injection, an example of traditional Chinese medicine injection, was screened and potential allergic components acting on the histamine H1 receptor were identified. A Ca(2+) flux assay showed that houttuyfonate and Yujin injection induced calcium release in a dose-dependent manner. This suggests that houttuyfonate is an activator of the histamine H1 receptor. The mechanism of houttuyfonate activation involves phosphorylation of the inositol-1,4,5-trisphosphate receptor. In conclusion, this two-dimensional method can rapidly detect and enrich target components isolated from the Yujin injection. This indicates that individuals with an overexpression of the histamine H1 receptor should be aware of possible allergic reactions when receiving the Yujin injection.

Screening of allergic components mediated by H(1)R in homoharringtonine injection through H(1)R/CMC-HPLC/MS.

It has been reported that the histamine H1 receptor (H(1)R) gene is up-regulated in patients with allergic rhinitis and H(1)R expression level strongly correlates with the severity of allergy symptoms. Drugs for therapy should avoid allergy symptoms, especially for patients with over-expressed H(1)R. Therefore, screening of the components which could induce H(1)R activation is urgently needed for drug safety evaluation. Homoharringtonine injection is a preparation for acute nonlymphocytic leukemia, which is approved by China Food and Drug Administration (CFDA) and US Food and Drug Administration. However, severely adverse reactions often occur with intravenous injection of the preparation. In present study, an H(1)R/CMC model was applied for capturing membrane retained components which could induce H(1)R activation. Retention components were enriched and analyzed by H(1)R/CMC-HPLC/MS. Homoharringtonine was recognized, separated and identified in homoharringtonine injection. Ca(2+) flux assay and p-IP3R expression founded that homoharringtonine retained by the H1 R/CMC model increased phosphorylation of IP3R and promoted cytosolic free Ca(2+) elevation in a dose-dependent manner which further verified the activity of homoharringtonine in activating the H1 R. In conclusion, homoharringtonine was screened and identified as a potential allergic factor. This provides an indication that a patient with over-expressed H1 R should be aware of possible allergic reaction when applying homoharringtonine injection.

A mouse model mimicking human first night effect for the evaluation of hypnotics.

In humans, a first night effect (FNE) is characterized by increased sleep latency and decreased total sleep time in an unfamiliar environment, but the mechanism and treatment options for this universally experienced acute insomnia are unclear. We continuously recorded electroencephalography (EEG) and electromyogram (EMG) and measured plasma corticosterone levels to develop a mouse FNE model by inducing acute insomnia in mice that have been placed in unfamiliar cage environments. The sleep latency of mice 'moved to clean cages' (MCC) was longer than that for mice 'moved to dirty ones' (MDC). As compared to MDC mice, MCC mice showed stronger decreases in the amount of non-rapid eye movement (non-REM, NREM) and REM sleep, with a lower power density of NREM sleep, increased fragmentation and decreased stage transitions from NREM sleep to wake, and higher variation in plasma corticosterone levels. Treatment of MCC mice with zolpidem, diazepam, raclopride, pyrilamine, except SCH23390 shortened NREM sleep latency. In addition, zolpidem significantly increased NREM and REM sleep with the increase in slow wave activity (1.00-2.75 Hz), while raclopride significantly increased NREM and REM sleep without changing the EEG power density in MCC mice, whereas diazepam increased sleep with a drastic decrease in power density of the frequency band between 1.00 and 4.00 Hz, diazepam also increased the frequency band between 9.75 and 24.75 Hz during NREM sleep. These results indicate that a MCC mouse can mimic a FNE phenotype of humans and that zolpidem and raclopride may be useful drugs to prevent acute insomnia, including FNE.