Spinal α-motoneurons directly innervate skeletal muscles and function as the final common path for movement and behavior. The processes that determine the excitability of motoneurons are critical for the execution of motor behavior. In fact, it has been noted that spinal motoneurons receive various neuromodulatory inputs, especially monoaminergic one. However, the roles of histamine and hypothalamic histaminergic innervation on spinal motoneurons and the underlying ionic mechanisms are still largely unknown. In the present study, by using the method of intracellular recording on rat spinal slices, we found that activation of either H or H receptor potentiated repetitive firing behavior and increased the excitability of spinal α-motoneurons. Both of blockage of K channels and activation of Na-Ca exchangers were involved in the H receptor-mediated excitation on spinal motoneurons, whereas the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels were responsible for the H receptor-mediated excitation. The results suggest that, through switching functional status of ion channels and exchangers coupled to histamine receptors, histamine effectively biases the excitability of the spinal α-motoneurons. In this way, the hypothalamospinal histaminergic innervation may directly modulate final motor outputs and actively regulate spinal motor reflexes and motor execution.
Animals ; Histamine ; pharmacology ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels ; metabolism ; Motor Neurons ; drug effects ; physiology ; Rats ; Receptors, Histamine H2 ; metabolism ; Sodium-Calcium Exchanger ; metabolism

Antipsychotic-induced weight gain (AIWG) is a common adverse effect of this treatment, particularly with second-generation antipsychotics, and it is a major health problem around the world. We aimed to review the progress of pharmacogenetic studies on AIWG in the Chinese population to compare the results for Chinese with other ethnic populations, identify the limitations and problems of current studies, and provide future research directions in China. Both English and Chinese electronic databases were searched to identify eligible studies. We determined that > 25 single-nucleotide polymorphisms in 19 genes have been investigated in association with AIWG in Chinese patients over the past few decades. HTR2C rs3813929 is the most frequently studied single-nucleotide polymorphism, and it seems to be the most strongly associated with AIWG in the Chinese population. However, many genes that have been reported to be associated with AIWG in other ethnic populations have not been included in Chinese studies. To explain the pharmacogenetic reasons for AIWG in the Chinese population, genome-wide association studies and multiple-center, standard, unified, and large samples are needed.
Antipsychotic Agents ; adverse effects ; Asian Continental Ancestry Group ; genetics ; China ; Genome-Wide Association Study ; Genotype ; Humans ; Lipid Metabolism ; genetics ; Neurosecretory Systems ; drug effects ; Pharmacogenomic Testing ; Polymorphism, Single Nucleotide ; Receptors, Adrenergic ; genetics ; Receptors, Dopamine ; genetics ; Receptors, Histamine ; genetics ; Receptors, Serotonin ; genetics ; Weight Gain ; drug effects ; genetics

The ventral pallidum (VP) is a crucial component of the limbic loop of the basal ganglia and participates in the regulation of reward, motivation, and emotion. Although the VP receives afferent inputs from the central histaminergic system, little is known about the effect of histamine on the VP and the underlying receptor mechanism. Here, we showed that histamine, a hypothalamic-derived neuromodulator, directly depolarized and excited the GABAergic VP neurons which comprise a major cell type in the VP and are responsible for encoding cues of incentive salience and reward hedonics. Both postsynaptic histamine H1 and H2 receptors were found to be expressed in the GABAergic VP neurons and co-mediate the excitatory effect of histamine. These results suggested that the central histaminergic system may actively participate in VP-mediated motivational and emotional behaviors via direct modulation of the GABAergic VP neurons. Our findings also have implications for the role of histamine and the central histaminergic system in psychiatric disorders.
Action Potentials ; drug effects ; Animals ; Basal Forebrain ; cytology ; Dimaprit ; pharmacology ; Dose-Response Relationship, Drug ; Electric Stimulation ; Female ; GABAergic Neurons ; drug effects ; Histamine ; pharmacology ; Histamine Agonists ; pharmacology ; Lysine ; analogs & derivatives ; metabolism ; Male ; Patch-Clamp Techniques ; Pyridines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Histamine H1 ; metabolism ; Receptors, Histamine H2 ; metabolism ; Sodium Channel Blockers ; pharmacology ; Tetrodotoxin ; pharmacology ; gamma-Aminobutyric Acid ; metabolism

Cyproheptadine (CPH), a first-generation antihistamine, enhances the delayed rectifier outward K current (I) in mouse cortical neurons through a sigma-1 receptor-mediated protein kinase A pathway. In this study, we aimed to determine the effects of CPH on neuronal excitability in current-clamped pyramidal neurons in mouse medial prefrontal cortex slices. CPH (10 µmol/L) significantly reduced the current density required to generate action potentials (APs) and increased the instantaneous frequency evoked by a depolarizing current. CPH also depolarized the resting membrane potential (RMP), decreased the delay time to elicit an AP, and reduced the spike threshold potential. This effect of CPH was mimicked by a sigma-1 receptor agonist and eliminated by an antagonist. Application of tetraethylammonium (TEA) to block I channels hyperpolarized the RMP and reduced the instantaneous frequency of APs. TEA eliminated the effects of CPH on AP frequency and delay time, but had no effect on spike threshold or RMP. The current-voltage relationship showed that CPH increased the membrane depolarization in response to positive current pulses and hyperpolarization in response to negative current pulses, suggesting that other types of membrane ion channels might also be affected by CPH. These results suggest that CPH increases the excitability of medial prefrontal cortex neurons by regulating TEA-sensitive I channels as well as other TEA-insensitive K channels, probably I and inward-rectifier Kir channels. This effect of CPH may explain its apparent clinical efficacy as an antidepressant and antipsychotic.
Animals ; Cyproheptadine ; pharmacology ; Female ; Histamine H1 Antagonists ; pharmacology ; Membrane Potentials ; drug effects ; physiology ; Mice, Inbred C57BL ; Patch-Clamp Techniques ; Potassium Channel Blockers ; pharmacology ; Potassium Channels ; metabolism ; Prefrontal Cortex ; drug effects ; physiology ; Pyramidal Cells ; drug effects ; physiology ; Receptors, sigma ; agonists ; metabolism ; Tetraethylammonium ; pharmacology ; Tissue Culture Techniques

OBJECTIVETo identify a HEK293 cell line containing stably-transfected H3R gene, and to screen the novel non-imidazole compounds with H3R antagonist activity.

METHODSThe expression of rat H3 receptor in cell line was detected by RT-PCR and Western blot. An elevation of intercellular cAMP concentration induced by forskolin was measured as the index for screening compounds with H3R antagonist activity.

RESULTSThe H3R-transfected HEK-293 cells stably expressed high level of rat H3 receptor mRNA and protein. Forskolin significantly increased intercellular cAMP concentration in the H3R-transfected HEK-293 cells. H3R agonist (R)-α-methylhistamine inhibited the forskolin-induced production of intercellular cAMP. H3R antagonist thioperamide and newly synthesized non-imidazole compounds XHA23 and XHA25 blocked (R)-α- methylhistamine reversal of forskolin-induced cAMP formation in a concentration-dependent manner, and the IC50 values were 3.62 μmol/L, 0.49 μmol/L, 0.14 μmol/L, respectively.

CONCLUSIONThe H3R-transfected HEK293 cells stably express high level of rat H3 receptor, and can be used for screening compounds with H3R antagonist activity. The non-imidazole compounds XHA23 and XHA25 may have H3R antagonist activity.

Animals ; Drug Evaluation, Preclinical ; HEK293 Cells ; Histamine H3 Antagonists ; Humans ; Rats ; Receptors, Histamine H3 ; genetics ; metabolism ; Transfection

Endoscopic mucosal resection (EMR) results in the formation of iatrogenic gastric ulcers and the optimal treatments for such ulcers are still unclear. We aimed to evaluate the efficacy of rebamipide in the management of EMR-induced ulcers by comparing it with an H2 receptor antagonist. After EMR, patients were randomly assigned into either rebamipide or famotidine groups. All patients received a one-week lansoprazole 30 mg q.d. therapy followed by three-week famotidine (20 mg b.i.d.) or rebamipide (100 mg t.i.d.) therapy. Four weeks after the treatments, ulcer sizes, stages, bleeding rates, and ulcer-related symptoms were compared using endoscopy and a questionnaire. A total of 63 patients were enrolled in this study. Finally, 51 patients were analyzed, 26 in rebamipide and 25 in famotidine group. Baseline characteristics were not significantly different between the two groups. Four weeks after EMR, the two groups were comparable in terms of ulcer reduction ratio (P=0.297), and ulcer stage (P=1.000). Moreover, no difference was observed with regard to ulcer-related symptoms, drug compliance, adverse drug event rates, and bleeding rates. Our data suggest that rebamipide is not inferior to famotidine in healing iatrogenic gastric ulcers, and could be a therapeutic option in the treatment of such ulcers.
Adult ; Aged ; Aged, 80 and over ; Alanine/*analogs & derivatives/therapeutic use ; Anti-Ulcer Agents/*therapeutic use ; Endoscopy, Gastrointestinal/*adverse effects ; Famotidine/*therapeutic use ; Histamine H2 Antagonists/*therapeutic use ; Humans ; Iatrogenic Disease ; Male ; Middle Aged ; Pilot Projects ; Prospective Studies ; Quinolones/*therapeutic use ; Receptors, Histamine H2/metabolism ; Stomach Ulcer/*drug therapy/*etiology/pathology ; Wound Healing

OBJECTIVE: To observe expression and distribution of histamine H4 receptor in nasal mucosa in normal people and allergic rhinitis patients,and understand role of histamine H4 receptor in allergic rhinitis. METHOD: Select normal people and allergic rhinitis patients each 10, take the nasal mucosa, detect expression and distribution of histamine H4 receptor at proteins and transcription level respectively by immunohistochemical method and RT-PCR, and compared. RESULT: Histamine H4 receptor at proteins and transcription level were found in normal nasal mucosa (25 509 +/- 6 441, 0.42 +/- 0.08), increased significantly in nasal mucosa of allergic rhinitis patients (49 676 +/- 8 541, 0.69 +/- 0.11, P < 0.05), which in structural cells and immune cells. CONCLUSION Histamine H4 receptors exist in normal nasal mucosa, its express significantly enhance, flew histamine H4 receptor may be mediated histamine in pathogenesis of allergic rhinitis ,who is one of the ligands of histamine.
Case-Control Studies ; Humans ; Nasal Mucosa ; immunology ; metabolism ; pathology ; Receptors, G-Protein-Coupled ; metabolism ; Receptors, Histamine ; metabolism ; Receptors, Histamine H4 ; Rhinitis, Allergic, Perennial ; immunology ; metabolism ; pathology

OBJECTIVE: To discuss the treatment of H3R agonist, IMETIT, on the allergic rhinitis(AR) ,and the influence to mRNA of Substance P(SP) and Substance P Receptor (SP-R) in AR model of guinea pigs. METHOD: The severity of AR was assessed by allergic symptoms (sneezing, nasal rubbing and nose blocking). The changes in the nasal mucosa were studied by pathological methods. The expression of SP positive cell was detected by immunohistochemistry, and the expression of SP-R mRNA was detected by reverse transcriptive polymerase chain reaction (RT-PCR). RESULT: Histamine H3R agonists, IMETIT can effectively improve the AR symptoms, sneezing, nasal itching, nasal congestion, reduce the pathological changes in the nasal mucosa, cut down the SP secretion and SP-R mRNA expression. CONCLUSION Histamine H3R agonist, IMETIT can effectively relieve the symptoms of AR in guinea pigs, which is related to reducing SP secretion and SP-R mRNA expression.
Animals ; Female ; Guinea Pigs ; Imidazoles ; therapeutic use ; Male ; Receptors, Histamine H3 ; drug effects ; Receptors, Neurokinin-1 ; genetics ; metabolism ; Rhinitis, Allergic, Perennial ; drug therapy ; metabolism ; Substance P ; metabolism ; Thiourea ; analogs & derivatives ; therapeutic use

To investigate the effect of cetirizine hydrochloride on the expression of neurokinin 1 receptor (NK-1R) and cytokines production induced by substance P (SP) in HaCaT cells (a human epidermal keratinocyte cell line) and dermal fibroblasts. The effect of cetirizine on the expression of NK-1R protein was detected by flow cytometry and Western blotting analysis. The modulation of cetirizine on the production of interferon (IFN)-gamma, interleukin (IL)-1beta, IL-6 and IL-8 in HaCaT cells and fibroblasts was measured by ELISA. The results showed that cetirizine significantly inhibited the expression of NK-1R in HaCaT cells and fibroblasts. SP induced the production of IFN-gamma, IL-1beta and IL-8 in both cell types. Cetirizine 1-100 micromol x L(-1) inhibited SP-induced IL-1beta and IL-8 production in HaCaT cells and fibroblasts, while had no effect on the production of IFN-gamma in both cells. Both SP and cetirizine had no effect on the secretion of IL-6 in HaCaT cells and fibroblasts. These findings suggest that cetirizine may be involved in the treatment of SP-induced skin inflammation by inhibiting the expression of substance P receptor and regulation the production of IL-1beta and IL-8 in epidermal keratinocyte and dermal fibroblasts.
Anti-Allergic Agents ; pharmacology ; Cell Line ; Cetirizine ; pharmacology ; Fibroblasts ; cytology ; metabolism ; Histamine H1 Antagonists, Non-Sedating ; pharmacology ; Humans ; Interferon-gamma ; metabolism ; Interleukin-1beta ; metabolism ; Interleukin-8 ; metabolism ; Keratinocytes ; cytology ; metabolism ; Receptors, Neurokinin-1 ; metabolism ; Substance P ; pharmacology

OBJECTIVETo investigate the effects of histamine on the neurotoxicity induced by beta-amyloid(1-42)(Abeta42) in rat phaeochromocytoma (PC12) cells.

METHODSThe in vitro model of Alzheimer's disease was constructed with A beta42-treated PC12 cells. Cell morphology and MTT assay were used to evaluate the cell toxicity and histamine effects. The different histamine antagonists were applied to investigate the involvement of receptor subtypes.

RESULTThe neurotoxicity was induced by A beta42 in a concentration-dependent manner, which was reversed by histamine at concentration of 10(-7), 10(-6) mol/L. The effect was reversed by H(2) antagonist zolantidine and H(3)antagonist clobenpropit, but not by H(1) antagonist diphenhydramine.

CONCLUSIONHistamine reduces neurotoxicity induced by beta-amyloid(1-42), which may be mediated by H(2) and H(3)receptors.

Alzheimer Disease ; chemically induced ; metabolism ; prevention & control ; Amyloid beta-Peptides ; toxicity ; Animals ; Benzothiazoles ; pharmacology ; Diphenhydramine ; pharmacology ; Dose-Response Relationship, Drug ; Histamine ; pharmacology ; Histamine H2 Antagonists ; pharmacology ; Histamine H3 Antagonists ; pharmacology ; Imidazoles ; pharmacology ; Neuroprotective Agents ; metabolism ; pharmacology ; PC12 Cells ; Phenoxypropanolamines ; pharmacology ; Piperidines ; pharmacology ; Rats ; Receptors, Histamine H2 ; metabolism ; Receptors, Histamine H3 ; metabolism ; Thiourea ; analogs & derivatives ; pharmacology