An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
A class of histamine receptors discriminated by their pharmacology and mode of action. Most histamine H1 receptors operate through the inositol phosphate/diacylglycerol second messenger system. Among the many responses mediated by these receptors are smooth muscle contraction, increased vascular permeability, hormone release, and cerebral glyconeogenesis. (From Biochem Soc Trans 1992 Feb;20(1):122-5)
The secretion of histamine from mast cell and basophil granules by exocytosis. This can be initiated by a number of factors, all of which involve binding of IgE, cross-linked by antigen, to the mast cell or basophil's Fc receptors. Once released, histamine binds to a number of different target cell receptors and exerts a wide variety of effects.
A class of histamine receptors discriminated by their pharmacology and mode of action. Histamine H2 receptors act via G-proteins to stimulate ADENYLYL CYCLASES. Among the many responses mediated by these receptors are gastric acid secretion, smooth muscle relaxation, inotropic and chronotropic effects on heart muscle, and inhibition of lymphocyte function. (From Biochem Soc Trans 1992 Feb;20(1):122-5)
Cell-surface proteins that bind histamine and trigger intracellular changes influencing the behavior of cells. Histamine receptors are widespread in the central nervous system and in peripheral tissues. Three types have been recognized and designated H1, H2, and H3. They differ in pharmacology, distribution, and mode of action.
Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.
Drugs that bind to and activate histamine receptors. Although they have been suggested for a variety of clinical applications histamine agonists have so far been more widely used in research than therapeutically.
Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.
A class of histamine receptors discriminated by their pharmacology and mode of action. Histamine H3 receptors were first recognized as inhibitory autoreceptors on histamine-containing nerve terminals and have since been shown to regulate the release of several neurotransmitters in the central and peripheral nervous systems. (From Biochem Soc Trans 1992 Feb;20(1):122-5)
Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.
An enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to histamine, forming N-methylhistamine, the major metabolite of histamine in man. EC 2.1.1.8.
A histamine H1 antagonist. It has mild hypnotic properties and some local anesthetic action and is used for allergies (including skin eruptions) both parenterally and locally. It is a common ingredient of cold remedies.
Histamine substituted in any position with one or more methyl groups. Many of these are agonists for the H1, H2, or both histamine receptors.
An enzyme that catalyzes the decarboxylation of histidine to histamine and carbon dioxide. It requires pyridoxal phosphate in animal tissues, but not in microorganisms. EC 4.1.1.22.
A histamine H2 receptor agonist that is often used to study the activity of histamine and its receptors.
Drugs that selectively bind to but do not activate HISTAMINE H3 RECEPTORS. They have been used to correct SLEEP WAKE DISORDERS and MEMORY DISORDERS.
Drugs used for their actions on histaminergic systems. Included are drugs that act at histamine receptors, affect the life cycle of histamine, or affect the state of histaminergic cells.
A histamine congener, it competitively inhibits HISTAMINE binding to HISTAMINE H2 RECEPTORS. Cimetidine has a range of pharmacological actions. It inhibits GASTRIC ACID secretion, as well as PEPSIN and GASTRIN output.
A histamine H1 antagonist used in allergic reactions, hay fever, rhinitis, urticaria, and asthma. It has also been used in veterinary applications. One of the most widely used of the classical antihistaminics, it generally causes less drowsiness and sedation than PROMETHAZINE.
A histamine H2 receptor antagonist that is used as an anti-ulcer agent.
A histamine H1 antagonist used as an antiemetic, antitussive, for dermatoses and pruritus, for hypersensitivity reactions, as a hypnotic, an antiparkinson, and as an ingredient in common cold preparations. It has some undesired antimuscarinic and sedative effects.
Granulated cells that are found in almost all tissues, most abundantly in the skin and the gastrointestinal tract. Like the BASOPHILS, mast cells contain large amounts of HISTAMINE and HEPARIN. Unlike basophils, mast cells normally remain in the tissues and do not circulate in the blood. Mast cells, derived from the bone marrow stem cells, are regulated by the STEM CELL FACTOR.
A potent mast cell degranulator. It is involved in histamine release.
Granular leukocytes characterized by a relatively pale-staining, lobate nucleus and cytoplasm containing coarse dark-staining granules of variable size and stainable by basic dyes.
A highly potent and specific histamine H2 receptor agonist. It has been used diagnostically as a gastric secretion indicator.
A photographic fixative used also in the manufacture of resins. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance may reasonably be anticipated to be a carcinogen (Merck Index, 9th ed). Many of its derivatives are ANTITHYROID AGENTS and/or FREE RADICAL SCAVENGERS.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
An acute hypersensitivity reaction due to exposure to a previously encountered ANTIGEN. The reaction may include rapidly progressing URTICARIA, respiratory distress, vascular collapse, systemic SHOCK, and death.
An antagonist of histamine that appears to block both H2 and H3 histamine receptors. It has been used in the treatment of ulcers.
A class of non-sedating drugs that bind to but do not activate histamine receptors (DRUG INVERSE AGONISM), thereby blocking the actions of histamine or histamine agonists. These antihistamines represent a heterogenous group of compounds with differing chemical structures, adverse effects, distribution, and metabolism. Compared to the early (first generation) antihistamines, these non-sedating antihistamines have greater receptor specificity, lower penetration of BLOOD-BRAIN BARRIER, and are less likely to cause drowsiness or psychomotor impairment.
Tests involving inhalation of allergens (nebulized or in dust form), nebulized pharmacologically active solutions (e.g., histamine, methacholine), or control solutions, followed by assessment of respiratory function. These tests are used in the diagnosis of asthma.
A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers.
Histamine H1 antagonist used in allergic rhinitis; ASTHMA; and URTICARIA. It is a component of COUGH and COLD medicines. It may cause drowsiness.
An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).
A chromone complex that acts by inhibiting the release of chemical mediators from sensitized mast cells. It is used in the prophylactic treatment of both allergic and exercise-induced asthma, but does not affect an established asthmatic attack.
An intense itching sensation that produces the urge to rub or scratch the skin to obtain relief.
A selective histamine H1-receptor antagonist devoid of central nervous system depressant activity. The drug was used for ALLERGY but withdrawn due to causing LONG QT SYNDROME.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A competitive histamine H2-receptor antagonist. Its main pharmacodynamic effect is the inhibition of gastric secretion.
A group of enzymes including those oxidizing primary monoamines, diamines, and histamine. They are copper proteins, and, as their action depends on a carbonyl group, they are sensitive to inhibition by semicarbazide.
The liquid secretion of the stomach mucosa consisting of hydrochloric acid (GASTRIC ACID); PEPSINOGENS; INTRINSIC FACTOR; GASTRIN; MUCUS; and the bicarbonate ion (BICARBONATES). (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p651)
Lining of the STOMACH, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. The surface cells produce MUCUS that protects the stomach from attack by digestive acid and enzymes. When the epithelium invaginates into the LAMINA PROPRIA at various region of the stomach (CARDIA; GASTRIC FUNDUS; and PYLORUS), different tubular gastric glands are formed. These glands consist of cells that secrete mucus, enzymes, HYDROCHLORIC ACID, or hormones.
A group of LEUKOTRIENES; (LTC4; LTD4; and LTE4) that is the major mediator of BRONCHOCONSTRICTION; HYPERSENSITIVITY; and other allergic reactions. Earlier studies described a "slow-reacting substance of ANAPHYLAXIS" released from lung by cobra venom or after anaphylactic shock. The relationship between SRS-A leukotrienes was established by UV which showed the presence of the conjugated triene. (From Merck Index, 11th ed)
Hydrochloric acid present in GASTRIC JUICE.
A potent second-generation histamine H1 antagonist that is effective in the treatment of allergic rhinitis, chronic urticaria, and pollen-induced asthma. Unlike many traditional antihistamines, it does not cause drowsiness or anticholinergic side effects.
A group of compounds that are derivatives of beta-methylacetylcholine (methacholine).
A synthetic pentapeptide that has effects like gastrin when given parenterally. It stimulates the secretion of gastric acid, pepsin, and intrinsic factor, and has been used as a diagnostic aid.
A cycloheptathiophene blocker of histamine H1 receptors and release of inflammatory mediators. It has been proposed for the treatment of asthma, rhinitis, skin allergies, and anaphylaxis.
A histamine H1 antagonist with low sedative action but frequent gastrointestinal irritation. It is used to treat ASTHMA; HAY FEVER; URTICARIA; and RHINITIS; and also in veterinary applications. Tripelennamine is administered by various routes, including topically.
The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.
Agents that are used to treat allergic reactions. Most of these drugs act by preventing the release of inflammatory mediators or inhibiting the actions of released mediators on their target cells. (From AMA Drug Evaluations Annual, 1994, p475)
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.
Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.
The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.
Neuroendocrine cells in the glands of the GASTRIC MUCOSA. They produce HISTAMINE and peptides such as CHROMOGRANINS. ECL cells respond to GASTRIN by releasing histamine which acts as a paracrine stimulator of the release of HYDROCHLORIC ACID from the GASTRIC PARIETAL CELLS.
Histidine substituted in any position with one or more methyl groups.
An evanescent cutaneous reaction occurring when antibody is injected into a local area on the skin and antigen is subsequently injected intravenously along with a dye. The dye makes the rapidly occurring capillary dilatation and increased vascular permeability readily visible by leakage into the reaction site. PCA is a sensitive reaction for detecting very small quantities of antibodies and is also a method for studying the mechanisms of immediate hypersensitivity.
A family of gastrointestinal peptide hormones that excite the secretion of GASTRIC JUICE. They may also occur in the central nervous system where they are presumed to be neurotransmitters.
A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.
A family of hexahydropyridines.
A plant genus of the family FABACEAE that is the source of mucuna gum.
An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Application of allergens to the nasal mucosa. Interpretation includes observation of nasal symptoms, rhinoscopy, and rhinomanometry. Nasal provocation tests are used in the diagnosis of nasal hypersensitivity, including RHINITIS, ALLERGIC, SEASONAL.
The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.
Spasmodic contraction of the smooth muscle of the bronchi.
A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.
Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).
Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.
Abnormal passage communicating with the STOMACH.
Rounded or pyramidal cells of the GASTRIC GLANDS. They secrete HYDROCHLORIC ACID and produce gastric intrinsic factor, a glycoprotein that binds VITAMIN B12.
Hypersensitivity reactions which occur within minutes of exposure to challenging antigen due to the release of histamine which follows the antigen-antibody reaction and causes smooth muscle contraction and increased vascular permeability.
A histamine H1 antagonist used as the hydrogen fumarate in hay fever, rhinitis, allergic skin conditions, and pruritus. It causes drowsiness.
A subtype of enteroendocrine cells found in the gastrointestinal MUCOSA, particularly in the glands of PYLORIC ANTRUM; DUODENUM; and ILEUM. These cells secrete mainly SEROTONIN and some neuropeptides. Their secretory granules stain readily with silver (argentaffin stain).
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
A vascular reaction of the skin characterized by erythema and wheal formation due to localized increase of vascular permeability. The causative mechanism may be allergy, infection, or stress.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Antihistamine drug now withdrawn from the market in many countries because of rare but potentially fatal side effects.
The forcing into the skin of liquid medication, nutrient, or other fluid through a hollow needle, piercing the top skin layer.
A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
A histamine analog and H1 receptor agonist that serves as a vasodilator. It is used in MENIERE DISEASE and in vascular headaches but may exacerbate bronchial asthma and peptic ulcers.
A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.
Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.
A serotonin antagonist and a histamine H1 blocker used as antipruritic, appetite stimulant, antiallergic, and for the post-gastrectomy dumping syndrome, etc.
The sudden, forceful, involuntary expulsion of air from the NOSE and MOUTH caused by irritation to the MUCOUS MEMBRANES of the upper RESPIRATORY TRACT.

Major changes in the brain histamine system of the ground squirrel Citellus lateralis during hibernation. (1/3980)

Hibernation in mammals such as the rodent hibernator Citellus lateralis is a physiological state in which CNS activity is endogenously maintained at a very low, but functionally responsive, level. The neurotransmitter histamine is involved in the regulation of diurnal rhythms and body temperature in nonhibernators and, therefore, could likely play an important role in maintaining the hibernating state. In this study, we show that histamine neuronal systems undergo major changes during hibernation that are consistent with such a role. Immunohistochemical mapping of histaminergic fibers in the brains of hibernating and nonhibernating golden-mantled ground squirrels (C. lateralis) showed a clear increase in fiber density during the hibernating state. The tissue levels of histamine and its first metabolite tele-methylhistamine were also elevated throughout the brain of hibernating animals, suggesting an increase in histamine turnover during hibernation, which occurs without an increase in histidine decarboxylase mRNA expression. This hibernation-related apparent augmentation of histaminergic neurotransmission was particularly evident in the hypothalamus and hippocampus, areas of importance to the control of the hibernating state, in which tele-methylhistamine levels were increased more than threefold. These changes in the histamine neuronal system differ from those reported for the metabolic pattern in other monoaminergic systems during hibernation, which generally indicate a decrease in turnover. Our results suggest that the influence of histamine neuronal systems may be important in controlling CNS activity during hibernation.  (+info)

Comparison of functional antagonism between isoproterenol and M2 muscarinic receptors in guinea pig ileum and trachea. (2/3980)

The ability of the M2 muscarinic receptor to mediate an inhibition of the relaxant effects of forskolin and isoproterenol was investigated in guinea pig ileum and trachea. In some experiments, trachea was first treated with 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) mustard to inactivate M3 receptors. The contractile response to oxotremorine-M was measured subsequently in the presence of both histamine (10 microM) and isoproterenol (10 nM). Under these conditions, [[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5, 11-dihydro-6H-pyrido[2,3b]-[1,4]benzodiazepine-6-one (AF-DX 116) antagonized the contractile response to oxotremorine-M in a manner consistent with an M3 mechanism. However, when the same experiment was repeated using forskolin (4 microM) instead of isoproterenol, the response to oxotremorine-M exhibited greater potency and was antagonized by AF-DX 116 in a manner consistent with an M2 mechanism. We also measured the effects of pertussis toxin treatment on the ability of isoproterenol to inhibit the contraction elicited by a single concentration of either histamine (0.3 microM) or oxotremorine-M (40 nM) in both the ileum and trachea. Pertussis toxin treatment had no significant effect on the potency of isoproterenol for inhibiting histamine-induced contractions in the ileum and trachea. In contrast, pertussis toxin treatment enhanced the relaxant potency of isoproterenol against oxotremorine-M-induced contractions in the ileum but not in the trachea. Also, pertussis toxin treatment enhanced the relaxant potency of forskolin against oxotremorine-M-induced contractions in the ileum and trachea. We investigated the relaxant potency of isoproterenol when very low, equi-effective (i.e., 20-34% of maximal response) concentrations of either histamine or oxotremorine-M were used to elicit contraction. Under these conditions, isoproterenol exhibited greater relaxant potency against histamine in the ileum but exhibited similar relaxant potencies against histamine and oxotremorine-M in the trachea. Following 4-DAMP mustard treatment, a low concentration of oxotremorine-M (10 nM) had no contractile effect in either the ileum or trachea. Nevertheless, in 4-DAMP mustard-treated tissue, oxotremorine-M (10 nM) reduced the relaxant potency of isoproterenol against histamine-induced contractions in the ileum, but not in the trachea. We conclude that in the trachea the M2 receptor mediates an inhibition of the relaxant effects of forskolin, but not isoproterenol, and the decreased relaxant potency of isoproterenol against contractions elicited by a muscarinic agonist relative to histamine is not due to activation of M2 receptors but rather to the greater contractile stimulus mediated by the M3 receptor compared with the H1 histamine receptor.  (+info)

Potent mast cell degranulation and vascular permeability triggered by urocortin through activation of corticotropin-releasing hormone receptors. (3/3980)

Urocortin (Ucn) is related to corticotropin-releasing hormone (CRH), and both are released in the brain under stress where they stimulate CRH 1 and 2 receptors (CRHR). Outside the brain, they may have proinflammatory actions through activation of mast cells, which are located perivascularly close to nerve endings and degranulate in response to acute psychological stress. Here, we report that a concentration of intradermal Ucn as low as 10 nM induced dose-dependent rat skin mast cell degranulation and increased vascular permeability. This effect appeared to be equipotent to that of calcitonin gene-related peptide and neurotensin. Ucn-induced skin vasodilation was inhibited by pretreatment with the mast cell stabilizer disodium cromoglycate (cromolyn) and was absent in the mast cell-deficient W/Wv mice. The selective nonpeptide CRH receptor 1 antagonist, antalarmin and the nonselective peptide antagonist astressin both reduced vascular permeability triggered by Ucn but not that by Substance P or histamine. In contrast, the peptide antagonist alpha-helical CRH-(9-41) reduced the effect of all three. The vasodilatory effect of Ucn was largely inhibited by pretreatment with H1 receptor antagonists, suggesting that histamine is the major mediator involved in vitro. Neuropeptide depletion of sensory neurons, treatment with the ganglionic blocker hexamethonium, or in situ skin infiltration with the local anesthetic lidocaine did not affect Ucn-induced vascular permeability, indicating that its in situ effect was not mediated through the peripheral nervous system. These results indicate that Ucn is one of the most potent triggers of rat mast cell degranulation and skin vascular permeability. This effect of Ucn may explain stress-induced disorders, such as atopic dermatitis or psoriasis, and may lead to new forms of treatment.  (+info)

Dynamic and quantitative Ca2+ measurements using improved cameleons. (4/3980)

Cameleons are genetically-encoded fluorescent indicators for Ca2+ based on green fluorescent protein variants and calmodulin (CaM). Because cameleons can be targeted genetically and imaged by one- or two-photon excitation microscopy, they offer great promise for monitoring Ca2+ in whole organisms, tissues, organelles, and submicroscopic environments in which measurements were previously impossible. However, the original cameleons suffered from significant pH interference, and their Ca2+-buffering and cross-reactivity with endogenous CaM signaling pathways was uncharacterized. We have now greatly reduced the pH-sensitivity of the cameleons by introducing mutations V68L and Q69K into the acceptor yellow green fluorescent protein. The resulting new cameleons permit Ca2+ measurements despite significant cytosolic acidification. When Ca2+ is elevated, the CaM and CaM-binding peptide fused together in a cameleon predominantly interact with each other rather than with free CaM and CaM-dependent enzymes. Therefore, if cameleons are overexpressed, the primary effect is likely to be the unavoidable increase in Ca2+ buffering rather than specific perturbation of CaM-dependent signaling.  (+info)

On the mechanism of histaminergic inhibition of glutamate release in the rat dentate gyrus. (5/3980)

1. Histaminergic depression of excitatory synaptic transmission in the rat dentate gyrus was investigated using extracellular and whole-cell patch-clamp recording techniques in vitro. 2. Application of histamine (10 microM, 5 min) depressed synaptic transmission in the dentate gyrus for 1 h. This depression was blocked by the selective antagonist of histamine H3 receptors, thioperamide (10 microM). 3. The magnitude of the depression caused by histamine was inversely related to the extracellular Ca2+ concentration. Application of the N-type calcium channel blocker omega-conotoxin (0. 5 or 1 microM) or the P/Q-type calcium channel blocker omega-agatoxin (800 nM) did not prevent depression of synaptic transmission by histamine. 4. The potassium channel blocker 4-aminopyridine (4-AP, 100 microM) enhanced synaptic transmission and reduced the depressant effect of histamine (10 microM). 4-AP reduced the effect of histamine more in 2 mM extracellular calcium than in 4 mM extracellular calcium. 5. Histamine (10 microM) did not affect the amplitude of miniature excitatory postsynaptic currents (mEPSCs) and had only a small effect on their frequency. 6. Histaminergic depression was not blocked by an inhibitor of serine/threonine protein kinases, H7 (100 microM), or by an inhibitor of tyrosine kinases, Lavendustin A (10 microM). 7. Application of adenosine (20 microM) or the adenosine A1 agonist N6-cyclopentyladenosine (CPA, 0.3 microM) completely occluded the effect of histamine (10 microM). 8. We conclude that histamine, acting on histamine H3 receptors, inhibits glutamate release by inhibiting presynaptic calcium entry, via a direct G-protein-mediated inhibition of multiple calcium channels. Histamine H3 receptors and adenosine A1 receptors act upon a common final effector to cause presynaptic inhibition.  (+info)

Mediators of anaphylaxis but not activated neutrophils augment cholinergic responses of equine small airways. (6/3980)

Neutrophilic inflammation in small airways (SA) and bronchospasm mediated via muscarinic receptors are features of chronic obstructive pulmonary disease in horses (COPD). Histamine, serotonin, and leukotrienes (LTs) are reported to be involved in the exacerbation of COPD, and currently, histamine has been shown to increase tension response to electrical field simulation (EFS) in equine SA. We tested the effects of these mediators and the effects of activated neutrophils on the cholinergic responses in SA. Histamine, serotonin, and LTD4 had a synergistic effect on EFS responses and only an additive effect on the tension response to exogenous ACh or methacholine. Atropine and TTX entirely eliminated the EFS-induced tension response in the presence of all three inflammatory mediators, indicating that augmentation of the EFS response applies only to the endogenous cholinergic response. Neutrophils isolated from control and COPD-affected horses were activated by zymosan, producing 18.1 +/- 2.3 and 25.0 +/- 2.3 nmol superoxide. 10(6) cells-1. 30 min-1, respectively. However, in contrast to the profound effect of mediators, incubation of SA for over 1 h in a suspension of up to 30 x 10(6) zymosan-treated neutrophils/ml did not significantly affect EFS responses of SA isolated from either control or COPD-affected horses. We conclude that in equine SA 1) the endogenous cholinergic responses are subject to strong facilitation by inflammatory mediators; 2) activated neutrophils do not affect cholinergic responses in SA; and 3) in acute bouts of equine COPD, histamine, LTD4, and serotonin (mediators primarily associated with type I allergic reaction) rather than mediators derived from neutrophils most likely contribute to increased cholinergic airway tone.  (+info)

Exhaled nitric oxide; relationship to clinicophysiological markers of asthma severity. (7/3980)

Bronchial asthma is an airway disorder associated with bronchial hyperresponsiveness, variable airflow obstruction and elevated levels of nitric oxide (NO) in exhaled air. The variables all reflect, in part, the underlying airway inflammation in this disease. To understand their interrelationships we have investigated the relationship between exhaled NO levels and clinicophysiological markers of asthma severity. Twenty-six steroid naive atopic asthmatics participated in the analysis. All were given diary cards and were asked to record their peak expiratory flow (PEF) rates twice daily together with their asthma symptom scores and beta-agonist use. Diary cards were collected 2 weeks later and measurements of exhaled NO levels, FEV1 and histamine bronchial hyperreactivity (PC20 histamine) were undertaken. Exhaled NO levels were significantly higher in our study population than in normal control subjects and correlated negatively with PC20 histamine (r = -0.51; P = 0.008) and positively with PEF diurnal variability (r = 0.58; P = 0.002), but not with symptom scores, beta-agonist use of FEV1 (%). We conclude that a significant relationship exists between exhaled NO levels and the two characteristic features and markers of asthma severity, namely bronchial hyperreactivity and PEF diurnal variability. The lack of correlation between symptom score and beta-agonist use, of FEV1 (%) predicted and exhaled NO suggests that these measures are reflective of differing aspects of asthma.  (+info)

Strain-dependent induction of allergic sensitization caused by peanut allergen DNA immunization in mice. (8/3980)

To investigate the potential application of allergen gene immunization in the modulation of food allergy, C3H/HeSn (C3H) mice received i.m. injections of pAra h2 plasmid DNA encoding one of the major peanut allergens, Ara h2. Three weeks following pDNA immunization, serum Ara h2-specific IgG2a, IgG1, but not IgE, were increased significantly in a dose-dependent manner. IgG1 was 30-fold higher in multiply compared with singly immunized mice. Ara h2 or peanut protein injection of immunized mice induced anaphylactic reactions, which were more severe in multiply immunized mice. Heat-inactivated immune serum induced passive cutaneous anaphylaxis, suggesting that anaphylaxis in C3H mice was mediated by IgG1. IgG1 responses were also induced by intradermal injection of pAra h2, and by i.m. injection of pOMC, the plasmid DNA encoding the major egg allergen protein, ovomucoid. To elucidate whether the pDNA immunization-induced anaphylaxis was a strain-dependent phenomenon, AKR/J and BALB/c mice also received multiple i.m. pAra h2 immunizations. Injection of peanut protein into these strains at weeks 3 or 5 following immunization did not induce reactions. Although IgG2a was increased significantly from week 2 in AKR/J mice and from week 4 in BALB/c mice and remained elevated for at least 6 wk, no IgG1 or IgE was detected. These results indicate that the type of immune responses to pDNA immunization in mice is strain dependent. Consequently, models for studying human allergen gene immunization require careful selection of suitable strains. In addition, this suggests that similar interindividual variation is likely in humans.  (+info)

Histamine is defined as a biogenic amine that is widely distributed throughout the body and is involved in various physiological functions. It is derived primarily from the amino acid histidine by the action of histidine decarboxylase. Histamine is stored in granules (along with heparin and proteases) within mast cells and basophils, and is released upon stimulation or degranulation of these cells.

Once released into the tissues and circulation, histamine exerts a wide range of pharmacological actions through its interaction with four types of G protein-coupled receptors (H1, H2, H3, and H4 receptors). Histamine's effects are diverse and include modulation of immune responses, contraction and relaxation of smooth muscle, increased vascular permeability, stimulation of gastric acid secretion, and regulation of neurotransmission.

Histamine is also a potent mediator of allergic reactions and inflammation, causing symptoms such as itching, sneezing, runny nose, and wheezing. Antihistamines are commonly used to block the actions of histamine at H1 receptors, providing relief from these symptoms.

Histamine H1 receptors are a type of G protein-coupled receptor found in various cells throughout the body, including those of the cardiovascular, gastrointestinal, and nervous systems. They are activated by the neurotransmitter histamine, which is released by mast cells and basophils in response to allergic reactions, inflammation, or immune responses.

When histamine binds to H1 receptors, it triggers a range of physiological responses that contribute to the symptoms of allergies, including vasodilation (leading to redness and warmth), increased vascular permeability (resulting in fluid leakage and swelling), and smooth muscle contraction (causing bronchoconstriction, gut cramping, and nasal congestion).

Histamine H1 receptors are also involved in the regulation of sleep-wake cycles, where they contribute to the promotion of wakefulness. Antihistamines that block H1 receptors are commonly used to treat allergies, hay fever, and other conditions associated with histamine release.

Histamine release is the process by which mast cells and basophils (types of white blood cells) release histamine, a type of chemical messenger or mediator, into the surrounding tissue fluid in response to an antigen-antibody reaction. This process is a key part of the body's immune response to foreign substances, such as allergens, and helps to initiate local inflammation, increase blood flow, and recruit other immune cells to the site of the reaction.

Histamine release can also occur in response to certain medications, physical trauma, or other stimuli. When histamine is released in large amounts, it can cause symptoms such as itching, sneezing, runny nose, watery eyes, and hives. In severe cases, it can lead to anaphylaxis, a life-threatening allergic reaction that requires immediate medical attention.

Histamine H2 receptors are a type of G protein-coupled receptor that are widely distributed throughout the body, including in the stomach, heart, and brain. They are activated by the neurotransmitter histamine, which is released by mast cells in response to an allergen or injury. When histamine binds to H2 receptors, it triggers a variety of physiological responses, such as increasing gastric acid secretion, regulating heart rate and contractility, and modulating neurotransmitter release in the brain. Histamine H2 receptor antagonists, also known as H2 blockers, are commonly used to treat gastroesophageal reflux disease (GERD) and peptic ulcers by reducing gastric acid production. Examples of H2 blockers include ranitidine (Zantac), famotidine (Pepcid), and cimetidine (Tagamet).

Histamine receptors are a type of cell surface receptor that bind to histamine, a biologically active compound involved in various physiological and pathophysiological processes in the body. There are four types of histamine receptors, designated H1, H2, H3, and H4, which are classified based on their specific responses to histamine.

Histamine receptors, Histamine (H1) are G protein-coupled receptors that are widely distributed in the body, including in the smooth muscle of blood vessels, respiratory tract, and gastrointestinal tract. When histamine binds to H1 receptors, it activates a signaling pathway that leads to the contraction of smooth muscle, increased vascular permeability, and stimulation of sensory nerve endings, resulting in symptoms such as itching, sneezing, and runny nose. Antihistamines, which are commonly used to treat allergies, work by blocking H1 receptors and preventing histamine from binding to them.

It's worth noting that while histamine has many important functions in the body, excessive or inappropriate activation of histamine receptors can lead to a range of symptoms and conditions, including allergic reactions, inflammation, and neuropsychiatric disorders.

Histamine antagonists, also known as histamine blockers or H1-blockers, are a class of medications that work by blocking the action of histamine, a substance in the body that is released during an allergic reaction. Histamine causes many of the symptoms of an allergic response, such as itching, sneezing, runny nose, and hives. By blocking the effects of histamine, these medications can help to relieve or prevent allergy symptoms.

Histamine antagonists are often used to treat conditions such as hay fever, hives, and other allergic reactions. They may also be used to treat stomach ulcers caused by excessive production of stomach acid. Some examples of histamine antagonists include diphenhydramine (Benadryl), loratadine (Claritin), and famotidine (Pepcid).

It's important to note that while histamine antagonists can be effective at relieving allergy symptoms, they do not cure allergies or prevent the release of histamine. They simply block its effects. It's also worth noting that these medications can have side effects, such as drowsiness, dry mouth, and dizziness, so it's important to follow your healthcare provider's instructions carefully when taking them.

Histamine agonists are substances that bind to and activate histamine receptors, leading to the initiation or enhancement of various physiological responses. Histamine is a naturally occurring molecule that plays a key role in the body's immune and allergic responses, as well as in the regulation of sleep, wakefulness, and appetite.

There are four main types of histamine receptors (H1, H2, H3, and H4), each with distinct functions and signaling pathways. Histamine agonists can be selective for one or more of these receptor subtypes, depending on their pharmacological properties.

For example, H1 agonists are commonly used as decongestants and antihistamines to treat allergies, while H2 agonists are used to treat gastroesophageal reflux disease (GERD) and peptic ulcers. H3 agonists have been investigated for their potential therapeutic use in the treatment of neurological disorders such as Parkinson's disease and schizophrenia, while H4 agonists are being studied for their role in inflammation and immune regulation.

It is important to note that histamine agonists can also have adverse effects, particularly if they are not selective for a specific receptor subtype or if they are used at high doses. These effects may include increased heart rate, blood pressure, and bronchodilation (opening of the airways), as well as gastrointestinal symptoms such as nausea, vomiting, and diarrhea.

Histamine H1 antagonists, also known as H1 blockers or antihistamines, are a class of medications that work by blocking the action of histamine at the H1 receptor. Histamine is a chemical mediator released by mast cells and basophils in response to an allergic reaction or injury. It causes various symptoms such as itching, sneezing, runny nose, and wheal and flare reactions (hives).

H1 antagonists prevent the binding of histamine to its receptor, thereby alleviating these symptoms. They are commonly used to treat allergic conditions such as hay fever, hives, and eczema, as well as motion sickness and insomnia. Examples of H1 antagonists include diphenhydramine (Benadryl), loratadine (Claritin), cetirizine (Zyrtec), and doxylamine (Unisom).

Histamine H3 receptors are a type of G protein-coupled receptor (GPCR) that are widely distributed throughout the central and peripheral nervous system. They are activated by the neurotransmitter histamine and function as autoreceptors, inhibiting the release of histamine from presynaptic nerve terminals. Histamine H3 receptors also modulate the activity of other neurotransmitters, such as acetylcholine, dopamine, norepinephrine, and serotonin, by regulating their synthesis, release, and uptake.

Histamine H3 receptors have been identified as potential targets for the treatment of various neurological and psychiatric disorders, including sleep disorders, attention deficit hyperactivity disorder (ADHD), schizophrenia, and drug addiction. Antagonists or inverse agonists of Histamine H3 receptors may enhance the release of neurotransmitters in the brain, leading to improved cognitive function, mood regulation, and reward processing. However, further research is needed to fully understand the therapeutic potential and safety profile of Histamine H3 receptor modulators.

Histamine H2 antagonists, also known as H2 blockers, are a class of medications that work by blocking the action of histamine on the H2 receptors in the stomach. Histamine is a chemical that is released by the body during an allergic reaction and can also be released by certain cells in the stomach in response to food or other stimuli. When histamine binds to the H2 receptors in the stomach, it triggers the release of acid. By blocking the action of histamine on these receptors, H2 antagonists reduce the amount of acid produced by the stomach, which can help to relieve symptoms such as heartburn, indigestion, and stomach ulcers. Examples of H2 antagonists include ranitidine (Zantac), famotidine (Pepcid), and cimetidine (Tagamet).

Histamine N-methyltransferase (HNMT) is an enzyme that plays a role in the metabolism and degradation of histamine, which is a biogenic amine involved in various physiological and pathophysiological processes. Histamine is released by mast cells and basophils during allergic reactions and inflammation, and it can cause symptoms such as itching, sneezing, runny nose, and wheezing.

HNMT is responsible for methylating the primary amino group of histamine, forming N-methylhistamine, which is then further metabolized by other enzymes. HNMT is primarily found in tissues such as the liver, kidney, and intestine, but it is also present in the brain and other organs.

Inhibition of HNMT has been suggested to be a potential therapeutic strategy for treating histamine-mediated disorders, such as allergies, asthma, and inflammatory bowel disease. However, more research is needed to fully understand the role of HNMT in these conditions and to develop effective treatments that target this enzyme.

Pyrilamine is an antihistamine drug that is primarily used to relieve allergic symptoms such as sneezing, itching, watery eyes, and runny nose. It works by blocking the action of histamine, a substance naturally produced by the body during an allergic reaction. Pyrilamine may also be used to treat motion sickness and to help with tension headaches or migraines.

Pyrilamine is available in various forms, including tablets, capsules, and syrup, and it can be taken with or without food. Common side effects of pyrilamine include dizziness, dry mouth, and drowsiness. It is important to avoid activities that require mental alertness, such as driving or operating heavy machinery, until you know how pyrilamine affects you.

Like all medications, pyrilamine should be taken under the supervision of a healthcare provider, who can determine the appropriate dosage and monitor for any potential side effects or interactions with other drugs. It is essential to follow the instructions provided by your healthcare provider carefully and not exceed the recommended dose.

Methylhistamines are not a recognized medical term or a specific medical condition. However, the term "methylhistamine" may refer to the metabolic breakdown product of the antihistamine drug, diphenhydramine, which is also known as N-methyldiphenhydramine or dimenhydrinate.

Diphenhydramine is a first-generation antihistamine that works by blocking the action of histamine, a chemical released during an allergic reaction. When diphenhydramine is metabolized in the body, it is converted into several breakdown products, including methylhistamines.

Methylhistamines are not known to have any specific pharmacological activity or clinical significance. However, they can be used as a marker for the presence of diphenhydramine or its metabolism in the body.

Histidine Decarboxylase is a medical term that refers to an enzyme found in various organisms, including humans. This enzyme plays a crucial role in the conversion of the amino acid L-histidine into histamine, which is a biogenic amine that acts as a neurotransmitter and inflammatory mediator in the human body.

Histidine decarboxylase is found in several tissues, including the central nervous system, gastrointestinal tract, and skin. It requires pyridoxal 5'-phosphate (PLP) as a cofactor for its enzymatic activity. Abnormal levels or activity of histidine decarboxylase have been implicated in several medical conditions, including allergic reactions, inflammation, and neuropsychiatric disorders.

Inhibitors of histidine decarboxylase are being investigated as potential therapeutic agents for the treatment of various diseases, such as mast cell-mediated disorders, gastrointestinal disorders, and neurological conditions associated with abnormal histamine levels.

Dimaprit is not a medical condition or disease. It is actually a synthetic peptide that acts as an agonist for certain types of receptors found in the body, specifically the H2 histamine receptors. These receptors are involved in various physiological processes, such as regulating gastric acid secretion and modulating immune responses.

As a research tool, Dimaprit is used to study the functions of H2 histamine receptors and their roles in different biological systems. It is not typically used as a therapeutic agent in clinical medicine.

Histamine H3 antagonists, also known as inverse agonists, are a class of drugs that block the activity of histamine at the H3 receptor. Histamine is a naturally occurring neurotransmitter and autacoid involved in various physiological functions, including the modulation of wakefulness and arousal, regulation of food intake, and control of blood pressure and fluid balance.

The H3 receptor is primarily located in the central nervous system (CNS) and acts as an auto-receptor on histamine-containing neurons to regulate the release of histamine. By blocking the activity of these receptors, histamine H3 antagonists increase the release of histamine in the CNS, which can lead to increased wakefulness and arousal.

Histamine H3 antagonists have been studied for their potential therapeutic use in various neurological and psychiatric disorders, including narcolepsy, attention deficit hyperactivity disorder (ADHD), and Alzheimer's disease. However, further research is needed to fully understand the clinical benefits and safety of these drugs.

Histamine agents are substances that can either increase or decrease the level or action of histamine in the body. Histamine is a chemical mediator released by mast cells and basophils in response to allergies, inflammation, or injury. It causes various symptoms such as itching, sneezing, runny nose, and wheal and flare reactions in the skin.

Histamine-releasing agents are substances that can trigger the release of histamine from mast cells and basophils. Examples include certain medications (e.g., opioids, vancomycin), physical stimuli (e.g., heat, exercise), and venoms (e.g., bee stings).

Histamine-inhibiting agents are substances that can block the action of histamine or prevent its release from mast cells and basophils. Examples include antihistamines, which bind to histamine receptors and prevent histamine from exerting its effects, and mast cell stabilizers, which prevent the degranulation of mast cells and the subsequent release of histamine and other mediators.

Histamine-enhancing agents are substances that can increase the level or action of histamine in the body. Examples include histamine agonists, which mimic the effects of histamine by binding to its receptors, and histamine precursors, which provide the building blocks for the synthesis of histamine.

Overall, histamine agents have important clinical implications in the management of allergies, inflammation, and other conditions associated with histamine release or action.

Cimetidine is a histamine-2 (H2) receptor antagonist, which is a type of medication that reduces the production of stomach acid. It works by blocking the action of histamine on the H2 receptors in the stomach, which are responsible for stimulating the release of stomach acid. By blocking these receptors, cimetidine reduces the amount of stomach acid produced and can help to relieve symptoms such as heartburn, indigestion, and stomach ulcers.

Cimetidine is available by prescription in various forms, including tablets, capsules, and liquid. It is typically taken two or three times a day, depending on the specific condition being treated. Common side effects of cimetidine may include headache, dizziness, diarrhea, and constipation.

In addition to its use in treating stomach acid-related conditions, cimetidine has also been studied for its potential anti-cancer properties. Some research suggests that it may help to enhance the immune system's response to cancer cells and reduce the growth of certain types of tumors. However, more research is needed to confirm these effects and determine the optimal dosage and duration of treatment.

Chlorpheniramine is an antihistamine medication that is used to relieve allergic symptoms caused by hay fever, hives, and other allergies. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Chlorpheniramine is available in various forms, including tablets, capsules, syrup, and injection.

Common side effects of chlorpheniramine include drowsiness, dry mouth, blurred vision, and dizziness. It may also cause more serious side effects such as rapid heartbeat, difficulty breathing, and confusion, especially in elderly people or those with underlying medical conditions. Chlorpheniramine should be used with caution and under the supervision of a healthcare provider, particularly in children, pregnant women, and people with medical conditions such as glaucoma, enlarged prostate, and respiratory disorders.

It is important to follow the dosage instructions carefully when taking chlorpheniramine, as taking too much can lead to overdose and serious complications. If you experience any unusual symptoms or have concerns about your medication, it is best to consult with a healthcare provider.

Metiamide is not generally considered a medical term, but it is a medication that has been used in the past. Medically, metiamide is defined as a synthetic histamine H2-receptor antagonist, which means it blocks the action of histamine at the H2 receptors in the stomach. This effect reduces gastric acid secretion and can be useful in treating gastroesophageal reflux disease (GERD), peptic ulcers, and other conditions associated with excessive stomach acid production.

However, metiamide has largely been replaced by other H2 blockers like cimetidine, ranitidine, and famotidine due to its association with a rare but serious side effect called agranulocytosis, which is a severe decrease in white blood cell count that can increase the risk of infections.

Diphenhydramine is an antihistamine medication used to relieve symptoms of allergies, such as sneezing, runny nose, and itchy or watery eyes. It works by blocking the action of histamine, a substance in the body that causes allergic reactions. Diphenhydramine can also be used to treat motion sickness, insomnia, and symptoms of the common cold.

In addition to its antihistamine effects, diphenhydramine also has anticholinergic properties, which means it can help to reduce secretions in the nose and throat, and may have a drying effect on the mouth and eyes. It is available over-the-counter in various forms, including tablets, capsules, liquid, and topical creams or ointments.

It's important to note that diphenhydramine can cause drowsiness, so it should be used with caution when operating heavy machinery or driving a vehicle. It may also interact with other medications, so it's important to speak with a healthcare provider before taking this medication.

Mast cells are a type of white blood cell that are found in connective tissues throughout the body, including the skin, respiratory tract, and gastrointestinal tract. They play an important role in the immune system and help to defend the body against pathogens by releasing chemicals such as histamine, heparin, and leukotrienes, which help to attract other immune cells to the site of infection or injury. Mast cells also play a role in allergic reactions, as they release histamine and other chemicals in response to exposure to an allergen, leading to symptoms such as itching, swelling, and redness. They are derived from hematopoietic stem cells in the bone marrow and mature in the tissues where they reside.

4-Methoxy-N-methylphenethylamine (also known as 4-MeO-N-MEPEA or 4-MeO-PMA) is a synthetic psychoactive substance that belongs to the phenethylamine class. It is a designer drug, which means it is manufactured and distributed for recreational use as an alternative to illegal drugs.

It acts as a stimulant and entactogen, producing effects similar to those of MDMA (ecstasy) but with less potency. The compound has been linked to several cases of severe intoxication, including fatalities, due to its ability to increase heart rate and blood pressure, cause dehydration, hyperthermia, and serotonin syndrome.

It is important to note that the use of 4-Methoxy-N-methylphenethylamine and other designer drugs can be dangerous and illegal in many jurisdictions. Always consult a medical professional for accurate information regarding specific substances.

Basophils are a type of white blood cell that are part of the immune system. They are granulocytes, which means they contain granules filled with chemicals that can be released in response to an infection or inflammation. Basophils are relatively rare, making up less than 1% of all white blood cells.

When basophils become activated, they release histamine and other chemical mediators that can contribute to allergic reactions, such as itching, swelling, and redness. They also play a role in inflammation, helping to recruit other immune cells to the site of an infection or injury.

Basophils can be identified under a microscope based on their characteristic staining properties. They are typically smaller than other granulocytes, such as neutrophils and eosinophils, and have a multi-lobed nucleus with dark purple-staining granules in the cytoplasm.

While basophils play an important role in the immune response, abnormal levels of basophils can be associated with various medical conditions, such as allergies, infections, and certain types of leukemia.

I'm sorry for any confusion, but "Impromidine" is not a widely recognized or established term in medical science or pharmacology. It does not appear to be listed in standard medical dictionaries or scientific literature as a drug, diagnostic agent, or medical condition.

If you have any more context or details about where you encountered this term, I'd be happy to help you try to figure out what it might refer to!

Thiourea is not a medical term, but a chemical compound. It's a colorless crystalline solid with the formula SC(NH2)2. Thiourea is used in some industrial processes and can be found in some laboratory reagents. It has been studied for its potential effects on certain medical conditions, such as its ability to protect against radiation damage, but it is not a medication or a treatment that is currently in clinical use.

I must clarify that the term "Guinea Pigs" is not typically used in medical definitions. However, in colloquial or informal language, it may refer to people who are used as the first to try out a new medical treatment or drug. This is known as being a "test subject" or "in a clinical trial."

In the field of scientific research, particularly in studies involving animals, guinea pigs are small rodents that are often used as experimental subjects due to their size, cost-effectiveness, and ease of handling. They are not actually pigs from Guinea, despite their name's origins being unclear. However, they do not exactly fit the description of being used in human medical experiments.

Anaphylaxis is a severe, life-threatening systemic allergic reaction that occurs suddenly after exposure to an allergen (a substance that triggers an allergic reaction) to which the person has previously been sensitized. The symptoms of anaphylaxis include rapid onset of symptoms such as itching, hives, swelling of the throat and tongue, difficulty breathing, wheezing, cough, chest tightness, rapid heartbeat, hypotension (low blood pressure), shock, and in severe cases, loss of consciousness and death. Anaphylaxis is a medical emergency that requires immediate treatment with epinephrine (adrenaline) and other supportive measures to stabilize the patient's condition.

Burimamide is a medication that was developed in the 1970s and is known as a histamine H2 receptor antagonist. It works by blocking the action of histamine, a substance in the body that is involved in allergic reactions and inflammation. Burimamide was originally developed to treat gastric ulcers, but it has largely been replaced by other medications with similar mechanisms of action, such as ranitidine and cimetidine, which have fewer side effects and are more effective.

The medical definition of 'Burimamide' is:

A synthetic histamine H2 receptor antagonist that was developed to treat gastric ulcers. It works by blocking the action of histamine at the H2 receptors in the stomach, reducing the production of stomach acid and promoting the healing of ulcers. Burimamide has largely been replaced by other medications with similar mechanisms of action, such as ranitidine and cimetidine, which have fewer side effects and are more effective.

Histamine H1 antagonists, non-sedating, also known as second-generation antihistamines, are medications that block the action of histamine at the H1 receptor without causing significant sedation. Histamine is a chemical mediator released by mast cells and basophils in response to an allergen, leading to allergic symptoms such as itching, sneezing, runny nose, and hives.

The non-sedating antihistamines have a higher affinity for the H1 receptor and are less lipophilic than first-generation antihistamines, which results in less penetration of the blood-brain barrier and reduced sedative effects. Examples of non-sedating antihistamines include cetirizine, levocetirizine, loratadine, desloratadine, fexofenadine, and rupatadine. These medications are commonly used to treat allergic rhinitis, urticaria, and angioedema.

Bronchial provocation tests are a group of medical tests used to assess the airway responsiveness of the lungs by challenging them with increasing doses of a specific stimulus, such as methacholine or histamine, which can cause bronchoconstriction (narrowing of the airways) in susceptible individuals. These tests are often performed to diagnose and monitor asthma and other respiratory conditions that may be associated with heightened airway responsiveness.

The most common type of bronchial provocation test is the methacholine challenge test, which involves inhaling increasing concentrations of methacholine aerosol via a nebulizer. The dose response is measured by monitoring lung function (usually through spirometry) before and after each exposure. A positive test is indicated when there is a significant decrease in forced expiratory volume in one second (FEV1) or other measures of airflow, which suggests bronchial hyperresponsiveness.

Other types of bronchial provocation tests include histamine challenges, exercise challenges, and mannitol challenges. These tests have specific indications, contraindications, and protocols that should be followed to ensure accurate results and patient safety. Bronchial provocation tests are typically conducted in a controlled clinical setting under the supervision of trained healthcare professionals.

Ranitidine is a histamine-2 (H2) blocker medication that works by reducing the amount of acid your stomach produces. It is commonly used to treat and prevent ulcers in the stomach and intestines, and to manage conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome.

Ranitidine is also used to treat gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn. Additionally, ranitidine can be used to prevent and treat upper gastrointestinal bleeding caused by stress or injury in critically ill patients.

The medication is available in both prescription and over-the-counter forms, and it comes in various forms, including tablets, capsules, and liquid solutions. As with any medication, ranitidine should be taken as directed by a healthcare professional, and its potential side effects and interactions with other medications should be carefully monitored.

Triprolidine is an antihistamine medication that is used to relieve symptoms caused by allergies, such as runny nose, sneezing, and itchy or watery eyes. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Triprolidine may also be used to help relieve symptoms of motion sickness.

It is important to note that this definition is for informational purposes only and should not be taken as medical advice. If you have any questions about triprolidine or its use, it is best to consult with a healthcare professional.

Immunoglobulin E (IgE) is a type of antibody that plays a key role in the immune response to parasitic infections and allergies. It is produced by B cells in response to stimulation by antigens, such as pollen, pet dander, or certain foods. Once produced, IgE binds to receptors on the surface of mast cells and basophils, which are immune cells found in tissues and blood respectively. When an individual with IgE antibodies encounters the allergen again, the cross-linking of IgE molecules bound to the FcεRI receptor triggers the release of mediators such as histamine, leukotrienes, prostaglandins, and various cytokines from these cells. These mediators cause the symptoms of an allergic reaction, such as itching, swelling, and redness. IgE also plays a role in protecting against certain parasitic infections by activating eosinophils, which can kill the parasites.

In summary, Immunoglobulin E (IgE) is a type of antibody that plays a crucial role in the immune response to allergens and parasitic infections, it binds to receptors on the surface of mast cells and basophils, when an individual with IgE antibodies encounters the allergen again, it triggers the release of mediators from these cells causing the symptoms of an allergic reaction.

Cromolyn sodium is a medication that belongs to a class of drugs known as mast cell stabilizers. It works by preventing the release of certain chemicals from mast cells, which are immune system cells found in various tissues throughout the body, including the skin, lungs, and gastrointestinal tract.

Mast cells play an important role in the body's allergic response. When a person is exposed to an allergen, such as pollen or pet dander, mast cells release chemicals like histamine, which can cause symptoms of an allergic reaction, such as itching, swelling, and inflammation.

Cromolyn sodium is used to prevent asthma attacks, hay fever, and other allergic reactions. It is often prescribed for people who have difficulty controlling their symptoms with other medications, such as inhaled corticosteroids or antihistamines.

The medication is available in various forms, including inhalers, nasal sprays, and eye drops. When used as an inhaler, cromolyn sodium is typically administered four times a day to prevent asthma symptoms. As a nasal spray or eye drop, it is usually used several times a day to prevent allergic rhinitis or conjunctivitis.

While cromolyn sodium can be effective in preventing allergic reactions, it does not provide immediate relief of symptoms. It may take several days or even weeks of regular use before the full benefits of the medication are felt.

Pruritus is a medical term derived from Latin, in which "prurire" means "to itch." It refers to an unpleasant sensation on the skin that provokes the desire or reflex to scratch. This can be caused by various factors, such as skin conditions (e.g., dryness, eczema, psoriasis), systemic diseases (e.g., liver disease, kidney failure), nerve disorders, psychological conditions, or reactions to certain medications.

Pruritus can significantly affect a person's quality of life, leading to sleep disturbances, anxiety, and depression. Proper identification and management of the underlying cause are essential for effective treatment.

Terfenadine is an antihistamine medication that has been used to treat symptoms of allergies such as hay fever, hives, and other allergic reactions. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Terfenadine was first approved for use in the United States in 1985, but it is no longer available in many countries due to concerns about rare but serious side effects related to heart rhythm disturbances. It has been replaced by other antihistamines that are considered safer and more effective.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Famotidine is a type of medication called an H2 blocker, or histamine-2 receptor antagonist. It works by reducing the amount of acid produced in the stomach. Famotidine is commonly used to treat and prevent ulcers in the stomach and intestines, and to manage conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome. It is also used to treat gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn.

Famotidine is available by prescription and over-the-counter in various forms, including tablets, capsules, and liquid. It is important to take famotidine exactly as directed by a healthcare professional, and to talk to them about any potential risks or side effects.

Gastric juice is a digestive fluid that is produced in the stomach. It is composed of several enzymes, including pepsin, which helps to break down proteins, and gastric amylase, which begins the digestion of carbohydrates. Gastric juice also contains hydrochloric acid, which creates a low pH environment in the stomach that is necessary for the activation of pepsin and the digestion of food. Additionally, gastric juice contains mucus, which helps to protect the lining of the stomach from the damaging effects of the hydrochloric acid. The production of gastric juice is controlled by hormones and the autonomic nervous system.

Gastric mucosa refers to the innermost lining of the stomach, which is in contact with the gastric lumen. It is a specialized mucous membrane that consists of epithelial cells, lamina propria, and a thin layer of smooth muscle. The surface epithelium is primarily made up of mucus-secreting cells (goblet cells) and parietal cells, which secrete hydrochloric acid and intrinsic factor, and chief cells, which produce pepsinogen.

The gastric mucosa has several important functions, including protection against self-digestion by the stomach's own digestive enzymes and hydrochloric acid. The mucus layer secreted by the epithelial cells forms a physical barrier that prevents the acidic contents of the stomach from damaging the underlying tissues. Additionally, the bicarbonate ions secreted by the surface epithelial cells help neutralize the acidity in the immediate vicinity of the mucosa.

The gastric mucosa is also responsible for the initial digestion of food through the action of hydrochloric acid and pepsin, an enzyme that breaks down proteins into smaller peptides. The intrinsic factor secreted by parietal cells plays a crucial role in the absorption of vitamin B12 in the small intestine.

The gastric mucosa is constantly exposed to potential damage from various factors, including acid, pepsin, and other digestive enzymes, as well as mechanical stress due to muscle contractions during digestion. To maintain its integrity, the gastric mucosa has a remarkable capacity for self-repair and regeneration. However, chronic exposure to noxious stimuli or certain medical conditions can lead to inflammation, erosions, ulcers, or even cancer of the gastric mucosa.

"SRS-A" is an older abbreviation for "Slow-Reacting Substance of Anaphylaxis," which refers to a group of molecules called "leukotrienes." Leukotrienes are mediators of inflammation and play a key role in the pathogenesis of asthma and other allergic diseases. They are produced by mast cells and basophils upon activation, and cause bronchoconstriction, increased vascular permeability, and mucus production.

The term "SRS-A" is not commonly used in modern medical literature, as it has been largely replaced by the more specific names of its individual components: LTC4, LTD4, and LTE4. These leukotrienes are now collectively referred to as the "cysteinyl leukotrienes."

Gastric acid, also known as stomach acid, is a digestive fluid produced in the stomach. It's primarily composed of hydrochloric acid (HCl), potassium chloride (KCl), and sodium chloride (NaCl). The pH of gastric acid is typically between 1.5 and 3.5, making it a strong acid that helps to break down food by denaturing proteins and activating digestive enzymes.

The production of gastric acid is regulated by the enteric nervous system and several hormones. The primary function of gastric acid is to initiate protein digestion, activate pepsinogen into the active enzyme pepsin, and kill most ingested microorganisms. However, an excess or deficiency in gastric acid secretion can lead to various gastrointestinal disorders such as gastritis, ulcers, and gastroesophageal reflux disease (GERD).

Cetirizine is an antihistamine medication that is used to relieve symptoms of allergies, such as hay fever, hives, and other allergic skin conditions. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Cetirizine is available over-the-counter and by prescription in various forms, including tablets, chewable tablets, and syrup.

The medical definition of Cetirizine is:

Cetirizine hydrochloride: A second-generation antihistamine with selective peripheral H1 receptor antagonist activity. A potent and long-acting inhibitor of the early and late phases of the allergic reaction, it exhibits anti-inflammatory properties and has a more favorable side effect profile than many other antihistamines. It is used in the management of allergic rhinitis, chronic urticaria, and angioedema.

Methacholine compounds are medications that are used as a diagnostic tool to help identify and confirm the presence of airway hyperresponsiveness in patients with respiratory symptoms such as cough, wheeze, or shortness of breath. These compounds act as bronchoconstrictors, causing narrowing of the airways in individuals who have heightened sensitivity and reactivity of their airways, such as those with asthma.

Methacholine is a synthetic derivative of acetylcholine, a neurotransmitter that mediates nerve impulse transmission in the body. When inhaled, methacholine binds to muscarinic receptors on the smooth muscle surrounding the airways, leading to their contraction and narrowing. The degree of bronchoconstriction is then measured to assess the patient's airway responsiveness.

It is important to note that methacholine compounds are not used as therapeutic agents but rather as diagnostic tools in a controlled medical setting under the supervision of healthcare professionals.

Pentagastrin is a synthetic polypeptide hormone that stimulates the release of gastrin and hydrochloric acid from the stomach. It is used diagnostically to test for conditions such as Zollinger-Ellison syndrome, a rare disorder in which tumors in the pancreas or duodenum produce excessive amounts of gastrin, leading to severe ulcers and other digestive problems.

Pentagastrin is typically administered intravenously, and its effects are monitored through blood tests that measure gastric acid secretion. It is a potent stimulant of gastric acid production, and its use is limited to diagnostic purposes due to the risk of adverse effects such as nausea, flushing, and increased heart rate.

Ketotifen is an antihistamine and mast cell stabilizer used in the prevention and treatment of allergic reactions. It works by blocking the release of histamine, a substance that causes allergic symptoms, and preventing the activation of mast cells, which play a key role in allergic responses. Ketotifen is available as an oral medication and is often used to treat chronic urticaria (hives) and other allergic conditions. It may also have some benefits in the treatment of asthma.

It's important to note that ketotifen should be taken under the supervision of a healthcare professional, as it can cause side effects such as drowsiness, dry mouth, and increased appetite. Additionally, it may interact with other medications, so it is important to inform your doctor of all medications you are taking before starting ketotifen.

Tripelennamine is not typically referred to as a "medical definition" in and of itself, but it is a medication with specific pharmacological properties. Tripelennamine is an older antihistamine drug that works by blocking the action of histamine, a substance in the body that causes allergic symptoms. It is primarily used to treat symptoms associated with allergies, such as runny nose, sneezing, and itchy or watery eyes.

Tripelennamine may also be used for its sedative properties to help manage anxiety or promote sleep. However, it is not commonly used in modern medical practice due to the availability of newer antihistamines with fewer side effects.

It's important to note that Tripelennamine can cause significant drowsiness and should be used with caution when operating heavy machinery or driving. It may also interact with other medications, so it is essential to inform your healthcare provider of all the drugs you are taking before starting Tripelennamine.

"Bronchi" are a pair of airways in the respiratory system that branch off from the trachea (windpipe) and lead to the lungs. They are responsible for delivering oxygen-rich air to the lungs and removing carbon dioxide during exhalation. The right bronchus is slightly larger and more vertical than the left, and they further divide into smaller branches called bronchioles within the lungs. Any abnormalities or diseases affecting the bronchi can impact lung function and overall respiratory health.

Anti-allergic agents, also known as antihistamines, are a class of medications used to treat allergies. They work by blocking the action of histamine, a substance in the body that is released during an allergic reaction and causes symptoms such as itching, sneezing, runny nose, and watery eyes.

There are two main types of antihistamines: first-generation and second-generation. First-generation antihistamines, such as diphenhydramine (Benadryl) and chlorpheniramine (Chlor-Trimeton), can cause drowsiness and other side effects, such as dry mouth and blurred vision. They are typically used for the treatment of short-term symptoms, such as those caused by seasonal allergies or a mild reaction to an insect bite.

Second-generation antihistamines, such as loratadine (Claritin) and cetirizine (Zyrtec), are less likely to cause drowsiness and other side effects. They are often used for the long-term treatment of chronic allergies, such as those caused by dust mites or pet dander.

In addition to their use in treating allergies, antihistamines may also be used to treat symptoms of motion sickness, insomnia, and anxiety. It is important to follow the instructions on the label when taking antihistamines and to talk to a healthcare provider if you have any questions or concerns about using these medications.

Smooth muscle, also known as involuntary muscle, is a type of muscle that is controlled by the autonomic nervous system and functions without conscious effort. These muscles are found in the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, as well as in the eyes, skin, and other areas of the body.

Smooth muscle fibers are shorter and narrower than skeletal muscle fibers and do not have striations or sarcomeres, which give skeletal muscle its striped appearance. Smooth muscle is controlled by the autonomic nervous system through the release of neurotransmitters such as acetylcholine and norepinephrine, which bind to receptors on the smooth muscle cells and cause them to contract or relax.

Smooth muscle plays an important role in many physiological processes, including digestion, circulation, respiration, and elimination. It can also contribute to various medical conditions, such as hypertension, gastrointestinal disorders, and genitourinary dysfunction, when it becomes overactive or underactive.

Airway resistance is a measure of the opposition to airflow during breathing, which is caused by the friction between the air and the walls of the respiratory tract. It is an important parameter in respiratory physiology because it can affect the work of breathing and gas exchange.

Airway resistance is usually expressed in units of cm H2O/L/s or Pa·s/m, and it can be measured during spontaneous breathing or during forced expiratory maneuvers, such as those used in pulmonary function testing. Increased airway resistance can result from a variety of conditions, including asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and bronchiectasis. Decreased airway resistance can be seen in conditions such as emphysema or after a successful bronchodilator treatment.

Bronchoconstriction is a medical term that refers to the narrowing of the airways in the lungs (the bronchi and bronchioles) due to the contraction of the smooth muscles surrounding them. This constriction can cause difficulty breathing, wheezing, coughing, and shortness of breath, which are common symptoms of asthma and other respiratory conditions.

Bronchoconstriction can be triggered by a variety of factors, including allergens, irritants, cold air, exercise, and emotional stress. In some cases, it may also be caused by certain medications, such as beta-blockers or nonsteroidal anti-inflammatory drugs (NSAIDs). Treatment for bronchoconstriction typically involves the use of bronchodilators, which are medications that help to relax the smooth muscles around the airways and widen them, making it easier to breathe.

The trachea, also known as the windpipe, is a tube-like structure in the respiratory system that connects the larynx (voice box) to the bronchi (the two branches leading to each lung). It is composed of several incomplete rings of cartilage and smooth muscle, which provide support and flexibility. The trachea plays a crucial role in directing incoming air to the lungs during inspiration and outgoing air to the larynx during expiration.

Enterochromaffin-like (ECL) cells are a type of neuroendocrine cell found in the stomach lining. They are located in the mucosa of the gastric glands and are responsible for producing and secreting hormones, such as histamine, that regulate gastric acid secretion. ECL cells are stimulated by the hormone gastrin, which is released by G cells in response to food intake or other stimuli. The histamine produced by ECL cells then acts on H2 receptors located on parietal cells, leading to the release of hydrochloric acid into the stomach.

ECL cells are named for their ability to take up and decarboxylate certain amines, such as serotonin and dopamine, which results in the formation of chromaffin granules that can be stained with chromium salts. These cells play an important role in regulating gastric acid secretion and are also involved in the development of some stomach disorders, such as gastrinomas and atrophic gastritis.

Methylhistidines are not a medical condition or disease, but rather refer to a group of biochemical compounds that are derived from the amino acid histidine. Specifically, methylhistidines are formed when histidine undergoes methylation, which is the addition of a methyl group (-CH3) to the histidine molecule.

There are three main types of methylhistidines that are commonly studied: 1-methylhistidine, 2-methylhistidine, and 3-methylhistidine. These compounds can be found in various tissues and fluids throughout the body, including muscles, urine, and cerebrospinal fluid.

In the medical field, methylhistidines are often used as markers of muscle breakdown and turnover. For example, increased levels of 1-methylhistidine in the urine have been associated with muscle wasting and other conditions that cause muscle damage or degeneration, such as muscular dystrophy and kidney disease. Similarly, elevated levels of 3-methylhistidine have been observed in patients with certain neuromuscular disorders, such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA).

Overall, while methylhistidines are not a medical condition themselves, they can provide valuable insights into various physiological processes and disease states.

Passive Cutaneous Anaphylaxis (PCA) is a type of localized or cutaneous hypersensitivity reaction that occurs when an individual who has been sensitized to a particular antigen is injected with the antigen along with a dye (usually Evans blue) and subsequently intravenously administered with a foreign protein, such as horse serum, that contains antibodies (IgG) against the antigen. The IgG antibodies passively transfer to the sensitized individual and bind to the antigen at the site of injection, forming immune complexes. These immune complexes then activate the complement system, leading to the release of mediators such as histamine, which causes localized vasodilation, increased vascular permeability, and extravasation of the dye into the surrounding tissues. As a result, a blue-colored wheal or skin blanching appears at the injection site, indicating a positive PCA reaction. This test is used to detect the presence of IgG antibodies in an individual's serum and to study the mechanisms of immune complex-mediated hypersensitivity reactions.

Gastrins are a group of hormones that are produced by G cells in the stomach lining. These hormones play an essential role in regulating gastric acid secretion and motor functions of the gastrointestinal tract. The most well-known gastrin is known as "gastrin-17," which is released into the bloodstream and stimulates the release of hydrochloric acid from parietal cells in the stomach lining.

Gastrins are stored in secretory granules within G cells, and their release is triggered by several factors, including the presence of food in the stomach, gastrin-releasing peptide (GRP), and vagus nerve stimulation. Once released, gastrins bind to specific receptors on parietal cells, leading to an increase in intracellular calcium levels and the activation of enzymes that promote hydrochloric acid secretion.

Abnormalities in gastrin production can lead to several gastrointestinal disorders, including gastrinomas (tumors that produce excessive amounts of gastrin), which can cause severe gastric acid hypersecretion and ulcers. Conversely, a deficiency in gastrin production can result in hypochlorhydria (low stomach acid levels) and impaired digestion.

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter that is found primarily in the gastrointestinal (GI) tract, blood platelets, and the central nervous system (CNS) of humans and other animals. It is produced by the conversion of the amino acid tryptophan to 5-hydroxytryptophan (5-HTP), and then to serotonin.

In the CNS, serotonin plays a role in regulating mood, appetite, sleep, memory, learning, and behavior, among other functions. It also acts as a vasoconstrictor, helping to regulate blood flow and blood pressure. In the GI tract, it is involved in peristalsis, the contraction and relaxation of muscles that moves food through the digestive system.

Serotonin is synthesized and stored in serotonergic neurons, which are nerve cells that use serotonin as their primary neurotransmitter. These neurons are found throughout the brain and spinal cord, and they communicate with other neurons by releasing serotonin into the synapse, the small gap between two neurons.

Abnormal levels of serotonin have been linked to a variety of disorders, including depression, anxiety, schizophrenia, and migraines. Medications that affect serotonin levels, such as selective serotonin reuptake inhibitors (SSRIs), are commonly used to treat these conditions.

Piperidines are not a medical term per se, but they are a class of organic compounds that have important applications in the pharmaceutical industry. Medically relevant piperidines include various drugs such as some antihistamines, antidepressants, and muscle relaxants.

A piperidine is a heterocyclic amine with a six-membered ring containing five carbon atoms and one nitrogen atom. The structure can be described as a cyclic secondary amine. Piperidines are found in some natural alkaloids, such as those derived from the pepper plant (Piper nigrum), which gives piperidines their name.

In a medical context, it is more common to encounter specific drugs that belong to the class of piperidines rather than the term itself.

Mucuna is a genus of tropical leguminous plants, and the term is often used in a medical context to refer to one specific species: Mucuna pruriens. This plant, also known as velvet bean, has been used in traditional medicine for various purposes, including the treatment of Parkinson's disease.

Mucuna pruriens contains high levels of L-dopa, a precursor to dopamine, which is a neurotransmitter that plays an important role in regulating movement and mood. As such, Mucuna has been studied as a potential alternative treatment for Parkinson's disease, which is characterized by low levels of dopamine in the brain.

It's worth noting that while some studies have suggested that Mucuna may be effective in reducing symptoms of Parkinson's disease, more research is needed to fully understand its safety and efficacy. Additionally, Mucuna can contain other compounds that may have negative effects, so it should only be used under the guidance of a healthcare professional.

In anatomical terms, the stomach is a muscular, J-shaped organ located in the upper left portion of the abdomen. It is part of the gastrointestinal tract and plays a crucial role in digestion. The stomach's primary functions include storing food, mixing it with digestive enzymes and hydrochloric acid to break down proteins, and slowly emptying the partially digested food into the small intestine for further absorption of nutrients.

The stomach is divided into several regions, including the cardia (the area nearest the esophagus), the fundus (the upper portion on the left side), the body (the main central part), and the pylorus (the narrowed region leading to the small intestine). The inner lining of the stomach, called the mucosa, is protected by a layer of mucus that prevents the digestive juices from damaging the stomach tissue itself.

In medical contexts, various conditions can affect the stomach, such as gastritis (inflammation of the stomach lining), peptic ulcers (sores in the stomach or duodenum), gastroesophageal reflux disease (GERD), and stomach cancer. Symptoms related to the stomach may include abdominal pain, bloating, nausea, vomiting, heartburn, and difficulty swallowing.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

Nasal provocation tests are a type of diagnostic procedure used in allergy testing to determine the specific allergens that cause a person's nasal symptoms. In this test, a small amount of an allergen is introduced into the patient's nostril using a spray or drops. The patient's response is then observed and measured for any signs of an allergic reaction, such as sneezing, runny nose, or congestion.

The test may be performed with a single allergen or with a series of allergens to identify which specific substances the patient is allergic to. The results of the test can help guide treatment decisions and management strategies for allergies, including immunotherapy (allergy shots) and avoidance measures.

It's important to note that nasal provocation tests should only be performed under the supervision of a trained healthcare professional, as there is a small risk of inducing a severe allergic reaction.

Capillary permeability refers to the ability of substances to pass through the walls of capillaries, which are the smallest blood vessels in the body. These tiny vessels connect the arterioles and venules, allowing for the exchange of nutrients, waste products, and gases between the blood and the surrounding tissues.

The capillary wall is composed of a single layer of endothelial cells that are held together by tight junctions. The permeability of these walls varies depending on the size and charge of the molecules attempting to pass through. Small, uncharged molecules such as water, oxygen, and carbon dioxide can easily diffuse through the capillary wall, while larger or charged molecules such as proteins and large ions have more difficulty passing through.

Increased capillary permeability can occur in response to inflammation, infection, or injury, allowing larger molecules and immune cells to enter the surrounding tissues. This can lead to swelling (edema) and tissue damage if not controlled. Decreased capillary permeability, on the other hand, can lead to impaired nutrient exchange and tissue hypoxia.

Overall, the permeability of capillaries is a critical factor in maintaining the health and function of tissues throughout the body.

Bronchial spasm refers to a sudden constriction or tightening of the muscles in the bronchial tubes, which are the airways that lead to the lungs. This constriction can cause symptoms such as coughing, wheezing, and difficulty breathing. Bronchial spasm is often associated with respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), and bronchitis. In these conditions, the airways are sensitive to various triggers such as allergens, irritants, or infections, which can cause the muscles in the airways to contract and narrow. This can make it difficult for air to flow in and out of the lungs, leading to symptoms such as shortness of breath, wheezing, and coughing. Bronchial spasm can be treated with medications that help to relax the muscles in the airways and open up the airways, such as bronchodilators and anti-inflammatory drugs.

Bradykinin is a naturally occurring peptide in the human body, consisting of nine amino acids. It is a potent vasodilator and increases the permeability of blood vessels, causing a local inflammatory response. Bradykinin is formed from the breakdown of certain proteins, such as kininogen, by enzymes called kininases or proteases, including kallikrein. It plays a role in several physiological processes, including pain transmission, blood pressure regulation, and the immune response. In some pathological conditions, such as hereditary angioedema, bradykinin levels can increase excessively, leading to symptoms like swelling, redness, and pain.

Imidazoles are a class of heterocyclic organic compounds that contain a double-bonded nitrogen atom and two additional nitrogen atoms in the ring. They have the chemical formula C3H4N2. In a medical context, imidazoles are commonly used as antifungal agents. Some examples of imidazole-derived antifungals include clotrimazole, miconazole, and ketoconazole. These medications work by inhibiting the synthesis of ergosterol, a key component of fungal cell membranes, leading to increased permeability and death of the fungal cells. Imidazoles may also have anti-inflammatory, antibacterial, and anticancer properties.

A chemical stimulation in a medical context refers to the process of activating or enhancing physiological or psychological responses in the body using chemical substances. These chemicals can interact with receptors on cells to trigger specific reactions, such as neurotransmitters and hormones that transmit signals within the nervous system and endocrine system.

Examples of chemical stimulation include the use of medications, drugs, or supplements that affect mood, alertness, pain perception, or other bodily functions. For instance, caffeine can chemically stimulate the central nervous system to increase alertness and decrease feelings of fatigue. Similarly, certain painkillers can chemically stimulate opioid receptors in the brain to reduce the perception of pain.

It's important to note that while chemical stimulation can have therapeutic benefits, it can also have adverse effects if used improperly or in excessive amounts. Therefore, it's essential to follow proper dosing instructions and consult with a healthcare provider before using any chemical substances for stimulation purposes.

Asthma is a chronic respiratory disease characterized by inflammation and narrowing of the airways, leading to symptoms such as wheezing, coughing, shortness of breath, and chest tightness. The airway obstruction in asthma is usually reversible, either spontaneously or with treatment.

The underlying cause of asthma involves a combination of genetic and environmental factors that result in hypersensitivity of the airways to certain triggers, such as allergens, irritants, viruses, exercise, and emotional stress. When these triggers are encountered, the airways constrict due to smooth muscle spasm, swell due to inflammation, and produce excess mucus, leading to the characteristic symptoms of asthma.

Asthma is typically managed with a combination of medications that include bronchodilators to relax the airway muscles, corticosteroids to reduce inflammation, and leukotriene modifiers or mast cell stabilizers to prevent allergic reactions. Avoiding triggers and monitoring symptoms are also important components of asthma management.

There are several types of asthma, including allergic asthma, non-allergic asthma, exercise-induced asthma, occupational asthma, and nocturnal asthma, each with its own set of triggers and treatment approaches. Proper diagnosis and management of asthma can help prevent exacerbations, improve quality of life, and reduce the risk of long-term complications.

Hypersensitivity is an exaggerated or inappropriate immune response to a substance that is generally harmless to most people. It's also known as an allergic reaction. This abnormal response can be caused by various types of immunological mechanisms, including antibody-mediated reactions (types I, II, and III) and cell-mediated reactions (type IV). The severity of the hypersensitivity reaction can range from mild discomfort to life-threatening conditions. Common examples of hypersensitivity reactions include allergic rhinitis, asthma, atopic dermatitis, food allergies, and anaphylaxis.

A gastric fistula is an abnormal connection or passage between the stomach and another organ or the skin surface. This condition can occur as a result of complications from surgery, injury, infection, or certain diseases such as cancer. Symptoms may include persistent drainage from the site of the fistula, pain, malnutrition, and infection. Treatment typically involves surgical repair of the fistula and management of any underlying conditions.

Parietal cells, also known as oxyntic cells, are a type of cell found in the gastric glands of the stomach lining. They play a crucial role in digestion by releasing hydrochloric acid and intrinsic factor into the stomach lumen. Hydrochloric acid is essential for breaking down food particles and creating an acidic environment that kills most bacteria, while intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine. Parietal cells are stimulated by histamine, acetylcholine, and gastrin to release their secretory products.

Hypersensitivity, Immediate: Also known as Type I hypersensitivity, it is an exaggerated and abnormal immune response that occurs within minutes to a few hours after exposure to a second dose of an allergen (a substance that triggers an allergic reaction). This type of hypersensitivity is mediated by immunoglobulin E (IgE) antibodies, which are produced by the immune system in response to the first exposure to the allergen. Upon subsequent exposures, these IgE antibodies bind to mast cells and basophils, leading to their degranulation and the release of mediators such as histamine, leukotrienes, and prostaglandins. These mediators cause a variety of symptoms, including itching, swelling, redness, and pain at the site of exposure, as well as systemic symptoms such as difficulty breathing, wheezing, and hypotension (low blood pressure). Examples of immediate hypersensitivity reactions include allergic asthma, hay fever, anaphylaxis, and some forms of food allergy.

Clemastine is an antihistamine medication that is used to relieve symptoms of allergies, such as runny nose, sneezing, and itchy or watery eyes. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Clemastine is available in oral tablet and liquid forms, and is typically taken twice daily with a full glass of water.

Common side effects of clemastine include drowsiness, dry mouth, headache, and upset stomach. It is important to avoid activities that require mental alertness, such as driving or operating heavy machinery, until you know how the medication affects you. Clemastine may also cause dizziness, so it is best to avoid getting up too quickly from a sitting or lying position.

Like all medications, clemastine should be taken only as directed by your healthcare provider. It is important to inform them of any other medications you are taking, as well as any medical conditions you may have, as clemastine can interact with certain drugs and may not be suitable for everyone.

Enterochromaffin cells, also known as Kulchitsky cells or enteroendocrine cells, are a type of neuroendocrine cell found in the epithelial lining of the gastrointestinal tract. These cells are responsible for producing and secreting a variety of hormones and neuropeptides that play important roles in regulating gastrointestinal motility, secretion, and sensation.

Enterochromaffin cells are named for their ability to take up chromaffin stains, which contain silver salts and oxidizing agents that react with the catecholamines stored within the cells. These cells can be further classified based on their morphology, location within the gastrointestinal tract, and the types of hormones they produce.

Some examples of hormones produced by enterochromaffin cells include serotonin (5-hydroxytryptamine), histamine, gastrin, somatostatin, and cholecystokinin. Serotonin is one of the most well-known hormones produced by these cells, and it plays a critical role in regulating gastrointestinal motility and secretion, as well as mood and cognition.

Abnormalities in enterochromaffin cell function have been implicated in a number of gastrointestinal disorders, including irritable bowel syndrome (IBS), functional dyspepsia, and gastroparesis. Additionally, mutations in genes associated with enterochromaffin cells have been linked to several inherited cancer syndromes, such as multiple endocrine neoplasia type 1 (MEN1) and neurofibromatosis type 1 (NF1).

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Urticaria, also known as hives, is an allergic reaction that appears on the skin. It is characterized by the rapid appearance of swollen, pale red bumps or plaques (wheals) on the skin, which are often accompanied by itching, stinging, or burning sensations. These wheals can vary in size and shape, and they may change location and appear in different places over a period of hours or days. Urticaria is usually caused by an allergic reaction to food, medication, or other substances, but it can also be triggered by physical factors such as heat, cold, pressure, or exercise. The condition is generally harmless, but severe cases of urticaria may indicate a more serious underlying medical issue and should be evaluated by a healthcare professional.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Astemizole is a second-generation antihistamine that was previously used to treat symptoms associated with allergies, such as hay fever, hives, and other allergic skin reactions. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. However, astemizole has been withdrawn from the market in many countries due to rare but serious side effects on the heart.

An "injection, intradermal" refers to a type of injection where a small quantity of a substance is introduced into the layer of skin between the epidermis and dermis, using a thin gauge needle. This technique is often used for diagnostic or research purposes, such as conducting allergy tests or administering immunizations in a way that stimulates a strong immune response. The injection site typically produces a small, raised bump (wheal) that disappears within a few hours. It's important to note that intradermal injections should be performed by trained medical professionals to minimize the risk of complications.

Guanidines are organic compounds that contain a guanidino group, which is a functional group with the formula -NH-C(=NH)-NH2. Guanidines can be found in various natural sources, including some animals, plants, and microorganisms. They also occur as byproducts of certain metabolic processes in the body.

In a medical context, guanidines are most commonly associated with the treatment of muscle weakness and neuromuscular disorders. The most well-known guanidine compound is probably guanidine hydrochloride, which has been used as a medication to treat conditions such as myasthenia gravis and Eaton-Lambert syndrome.

However, the use of guanidines as medications has declined in recent years due to their potential for toxicity and the development of safer and more effective treatments. Today, guanidines are mainly used in research settings to study various biological processes, including protein folding and aggregation, enzyme inhibition, and cell signaling.

Cyclic adenosine monophosphate (cAMP) is a key secondary messenger in many biological processes, including the regulation of metabolism, gene expression, and cellular excitability. It is synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase and is degraded by the enzyme phosphodiesterase.

In the body, cAMP plays a crucial role in mediating the effects of hormones and neurotransmitters on target cells. For example, when a hormone binds to its receptor on the surface of a cell, it can activate a G protein, which in turn activates adenylyl cyclase to produce cAMP. The increased levels of cAMP then activate various effector proteins, such as protein kinases, which go on to regulate various cellular processes.

Overall, the regulation of cAMP levels is critical for maintaining proper cellular function and homeostasis, and abnormalities in cAMP signaling have been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

The ileum is the third and final segment of the small intestine, located between the jejunum and the cecum (the beginning of the large intestine). It plays a crucial role in nutrient absorption, particularly for vitamin B12 and bile salts. The ileum is characterized by its thin, lined walls and the presence of Peyer's patches, which are part of the immune system and help surveil for pathogens.

Betahistine is a medication that is primarily used to treat symptoms associated with Ménière's disease, which is an inner ear disorder that can cause vertigo (dizziness), tinnitus (ringing in the ears), and hearing loss. Betahistine is thought to work by improving blood flow in the inner ear and reducing the pressure in the fluid-filled compartments of the ear.

Betahistine is a histamine analogue, which means that it has a similar chemical structure to histamine, a naturally occurring compound in the body that plays a role in various physiological processes, including the regulation of blood flow and inflammation. Betahistine acts as an agonist at H1 and H3 histamine receptors and as an antagonist at H2 receptors, which leads to its therapeutic effects on the inner ear.

The medication is available in tablet form and is typically taken two or three times a day, with or without food. The dosage may vary depending on the individual's response to treatment and any underlying medical conditions. Common side effects of betahistine include gastrointestinal symptoms such as nausea, vomiting, and diarrhea, as well as headache, dizziness, and dry mouth.

It is important to note that betahistine may interact with other medications, including certain antidepressants, antihistamines, and sedatives, so it is essential to inform your healthcare provider of all the medications you are taking before starting treatment with betahistine. Additionally, individuals with asthma or a history of peptic ulcers should use caution when taking this medication, as it may exacerbate these conditions.

Carbachol is a cholinergic agonist, which means it stimulates the parasympathetic nervous system by mimicking the action of acetylcholine, a neurotransmitter that is involved in transmitting signals between nerves and muscles. Carbachol binds to both muscarinic and nicotinic receptors, but its effects are more pronounced on muscarinic receptors.

Carbachol is used in medical treatments to produce miosis (pupil constriction), lower intraocular pressure, and stimulate gastrointestinal motility. It can also be used as a diagnostic tool to test for certain conditions such as Hirschsprung's disease.

Like any medication, carbachol can have side effects, including sweating, salivation, nausea, vomiting, diarrhea, bradycardia (slow heart rate), and bronchoconstriction (narrowing of the airways in the lungs). It should be used with caution and under the supervision of a healthcare professional.

A lung is a pair of spongy, elastic organs in the chest that work together to enable breathing. They are responsible for taking in oxygen and expelling carbon dioxide through the process of respiration. The left lung has two lobes, while the right lung has three lobes. The lungs are protected by the ribcage and are covered by a double-layered membrane called the pleura. The trachea divides into two bronchi, which further divide into smaller bronchioles, leading to millions of tiny air sacs called alveoli, where the exchange of gases occurs.

Cyproheptadine is an antihistamine and anticholinergic medication that is primarily used to treat symptoms of allergies, such as runny nose, sneezing, and itching. It works by blocking the action of histamine, a substance in the body that causes allergic reactions.

Cyproheptadine also has other uses, including the treatment of migraines and cluster headaches, appetite stimulation in people with certain medical conditions, and as a sedative in some cases. It is available in various forms, such as tablets, capsules, and syrup.

Like all medications, cyproheptadine can have side effects, including drowsiness, dry mouth, dizziness, and blurred vision. It is important to follow the dosage instructions carefully and talk to a healthcare provider if you experience any bothersome or persistent side effects.

Sneezing is an involuntary, forceful expulsion of air through the nose and mouth, often triggered by irritation or inflammation in the nasal passages. It is a protective reflex that helps to clear the upper respiratory tract of irritants such as dust, pollen, or foreign particles. The sneeze begins with a deep inspiration of air, followed by closure of the glottis (the opening between the vocal cords) and contraction of the chest and abdominal muscles. This builds up pressure in the lungs, which is then suddenly released through the nose and mouth as the glottis opens and the velum (the soft tissue at the back of the roof of the mouth) rises to block the nasal passage. The result is a powerful burst of air that can travel at speeds of up to 100 miles per hour, expelling mucus and any trapped irritants along with it.

The tele tautomer, Nτ-H-histamine, is preferred in solution as compared to the pros tautomer, Nπ-H-histamine. Histamine has two ... Histamine intolerance Histamine receptor antagonist Scombroid food poisoning Photic sneeze reflex Histamine Material Safety ... Sake contains histamine in the 20-40 mg/L range; wines contain it in the 2-10 mg/L range. Most histamine in the body is ... In humans, histamine exerts its effects primarily by binding to G protein-coupled histamine receptors, designated H1 through H4 ...
... boosting histamine levels in the brain can significantly improve performance in long-term memory tests. ... When they took a look at the brains of the mice, they saw that histamine levels were particularly high in a region called the ... As expected, histamine did have a positive impact on some participants memory test scores. For individuals with poorer ... Histamine and memory. Over recent decades, researchers have demonstrated an interesting relationship between increased ...
Sweden reports histamine outbreak from imported fish. By News Desk on April 15, 2021. ... The excessive levels can expose consumers to the risk of histamine, also known as scombroid, poisoning, said the Commission.… ... Italian authorities are investigating a case of fish fraud that led to several people suffering from histamine poisoning. ... Almost 20 people have fallen ill in Sweden this month from histamine poisoning in fish from Vietnam. ...
The best histamine-reducing foods are those made with high-quality, all-natural ingredients, which will help keep your adverse ... Histamine Lowering Foods Another way to deal with histamine intolerance is to consume a lot of histamine reducing foods. ... Colorado State University VIVO Pathophysiology: Histamine * American Journal of Clinical Nutrition: Histamine and Histamine ... What Is Histamine? Histamine is a chemical that occurs naturally in the body to help lessen the effects of allergic reactions. ...
Histamine fish poisoning results from the consumption of inadequately preserved and improperly refrigerated fish. ... Histamine fish poisoning is among the most common toxicities related to fish ingestion, constituting almost 40% of all seafood- ... encoded search term (Histamine Toxicity from Fish) and Histamine Toxicity from Fish What to Read Next on Medscape ... Previous terms for histamine fish poisoning were scombroid fish poisoning, pseudoallergic fish poisoning, histamine overdose, ...
Increasing histamine neurotransmission in Gilles de la Tourette syndrome. *Andreas Hartmann. 1,2,3, ... Hartmann, A., Worbe, Y. & Arnulf, I. Increasing histamine neurotransmission in Gilles de la Tourette syndrome. J Neurol 259, ... An inverse agonist of the histamine H(3) receptor improves wakefulness in narcolepsy: studies in orexin−/− mice and patients. ... a nonimidazole inverse agonist/antagonist at the human histamine H3 receptor: preclinical pharmacology. J Pharmacol Exp Ther ...
Histamine is a substance in the body thats released during an allergic reaction. ... Histamine. Say: HIS-tuh-meen. Histamine is a substance that the body releases during an allergic reaction. It can cause allergy ... When histamine affects the lungs, a person who has asthma may have breathing problems. ...
... amino group on the side chain of the ligand which is not very common for a simple heterocyclic derivative such as histamine. ... complexes with histamine ,svg style=vertical-align:-5.56926pt;width:251.39999px; id=M1 height=19.1625 version=1.1 ... Novel ruthenium(III) complexes with histamine (1a) and (1b) have been prepared and characterized by X-ray structure analysis. ... Histamine (4-(2-Aminoethyl)-1H-imidazole, see Scheme 2) is a molecule that performs various functions in the body, the most ...
Histamine could be an important molecule to developing new treatments for multiple sclerosis (MS) ... Scientists studied the direct effects of histamine and two similar molecules that bind specifically on histamine receptors 1 or ... the scientists analyzed the role of histamine in an animal model of multiple sclerosis and found that histamine plays a ... Histamine May be Possible Drug Target for Multiple Sclerosis. Published: 2011/01/31. Author: Federation of American Societies ...
Hazard - P - B - T - Risk Exempt. The use of amino acids, proteins and peptides is not considered to have any environmental impact. ...
Reveal for Histamine (PN 9548) is a qualitative lateral flow assay intended for visual screening of histamine at 50 parts-per- ... High levels of histamine may develop in fish species as they decompose, and the ingestion of histamine can cause scombroid ... for Histamine and Reveal Q+ for Histamine.. Reveal and Reveal Q+ assays are easy-to-use lateral flow tests that utilize a ... Reveal Q+ for Histamine (PN 9549) is a quantitative lateral flow assay designed to be read on Neogens Raptor® Integrated ...
... a Histamine H2-receptor antagonist, on the rate of gastric emptying was assessed in 24 uncomplicated duodenal ulcer patients ... Effect of histamine H2-receptor blockade on gastric emptying and serum gastrin in man Scott Med J. 1976 Jan;21(1):23-7. doi: ... The effect of orally administered metiamide, a Histamine H2-receptor antagonist, on the rate of gastric emptying was assessed ...
... Study Abstract. Background/aims: Food intolerance/ ... A standardized anonymous questionnaire with symptoms of HIT based on known symptoms and the 4 histamine receptors including ... malabsorption, particularly histamine intolerance (HIT), may cause nonspecific functional gastrointestinal and extraintestinal ...
... we investigated the effects of targeting the CXCR4 receptor using the histamine analog clobenpropit (CB). Monocytes were ... Here, we show that targeting CXCR4 with small amino compound such as the histamine analog clobenpropit (CB) inhibits ... To first assess the potential anti-inflammatory properties of histamine and the histamine analog CB, we took advantage of the ... We previously showed that histamine and the histamine analog clobenpropit (CB) through their engagement of CXCR4 exhibited a ...
We found that the histamine-induced DAG response was biphasic, in which a transient peak was followed by maintained elevated ... When stimulated by agonists of the histamine H1 receptor (H1R), TRPC6 activity decays to the baseline despite the continuous ... plateau, suggesting that desensitization of H1R takes place in the presence of histamine. The application of PKC inhibitor ... Histamine-induced TRPC6 Activity Decays in the Present of Histamine. The TRPC6 channel mediates Ca2+ influx in various ...
THE PLACE OF HISTAMINE IN NEUROHUMORAL TRANSMISSION Message Subject (Your Name) has forwarded a page to you from ...
Histamine forms postmortem by bacterial action on the amino acid, L-histidine. Histamine is heat-stable and survives thermal ... It is also indicated by elevated histamine levels in the muscle tissue. The presence of 50 ppm (5 mg/100 g) or more histamine ... 540.525 Scombrotoxin (Histamine)-forming Fish and Fishery Products--Decomposition and Histamine." The draft guidance, when ... Histamine level equal to or greater than 50 ppm but less than 500 ppm in at least two subsamples by both original and check ...
Hough LB Histamine and Psychotroic Drugs Psychopharmacol.Bull. 1980 16(1):36-38 ...
US-4536508-A chemical patent summary.
Do mosquitoes release histamine?. admin. September 30, 2019. Do mosquitoes release histamine?. When a mosquito bite breaks the ... Heres how it works: when something bothers the skin, like a mosquito bite, cells release a chemical, usually histamine. That ... The swelling around the bite is caused by histamine, which is produced by the immune system. ...
Histamine releasing factor (HRF), also known as translationally controlled tumor protein (TCTP), is a highly conserved, ... Potential role of histamine releasing factor (HRF) as a therapeutic target for treating asthma and allergy Susan M MacDonaldThe ... Potential role of histamine releasing factor (HRF) as a therapeutic target for treating asthma and allergy. ... Abstract: Histamine releasing factor (HRF), also known as translationally controlled tumor protein (TCTP), is a highly ...
Is there any arteriolar dilation at all in Type I HS? According to FA it is only postcapillary venules, but according to Goljan, in bee sting, arteriolar...
The Effect of Prior Bronchoconstriction on the Bronchial Response to Inhaled Histamine K F Chung; K F Chung ... K F Chung, B H Morgan, P D Smashall; The Effect of Prior Bronchoconstriction on the Bronchial Response to Inhaled Histamine. ...
Plasma urea as source of ammonium ion in gastric juice of histamine-stimulated dog American Journal of Physiology 165(3): 695- ... Ruoff, H.J.; Sewing, K.F. 1973: Cyclic amp in the rat gastric mucosa after penta gastrin histamine and carbachol Acta Hepato- ... Puşcaş, I.; Voicu, L. 1980: 3',5'cyclic AMP, histamine and carbonic anhydrase of the gastric mucosa Revista de ... Forte, J.G.; Forte, T.M.; Machen, T.E. 1975: Histamine-stimulated hydrogen ion secretion by in vitro piglet gastric mucosa ...
METHODS: The reaction mixture of malondialdehyde (MDA) and histamine (HA) at pH7.4, 37 degrees C was assayed by high ... Li I, Li U, Sheng H, Yin A, Substantial reaction between histamine and malondialdehyde: a new observation of carbonyl stress. ... Substantial reaction between histamine and malondialdehyde: a new observation of carbonyl stress.. ... OBJECTIVES: To explore the mechanism of carbonyl stress-related toxification on neurotransmitter histamine and the potential de ...
... and variations in genes influencing the action of histamine may explain the inconsistency between previous studies. Genes ... Histamine may mediate the effects of food additives on ADHD symptoms, ... The role of histamine degradation gene polymorphisms in moderating the effects of food additives on childrens ADHD symptoms Am ... Conclusions: Histamine may mediate the effects of food additives on ADHD symptoms, and variations in genes influencing the ...
profile of European Histamine Research Society from the Yearbook of International Organizations, a service of the UIA. ... Promote knowledge and research within all aspects of histamine and related fields. ...

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