substance released by mast cells during the allergic reaction. This substance causes many of the symptoms of allergies.

A substance released by basophils in mast cells during allergic reactions. The pharmacologic effects of histamine include dilating blood vessels and stimulating gastric secretion.

A major vasoactive amine and inflammatory chemical messenger released from mast cell and basophil granules. It is a monoamine neurotransmitter.

A mediator of inflammatory reactions in the body, which may be part of an allergic reaction. Present in preformed granules in mast cells and basophils.

Small molecule derived from the amino acid histidine, released from mast cells and basophils in allergic reactions. Causes irritation, dilation of blood vessels, and contraction of smooth muscle.

( hiss-tuh-meen) A substance released by injured cells that causes blood vessels to dilate during an inflammatory response.

A body chemical involved in signaling for immune and allergic reactions.

a hormone/chemical transmitter involved in local immune responses. When released, histamine causes blood vessels to dilate and increase in permeability, allowing fluid and cells of the immune system to leak from the bloodstream. In normal cases, this allows cells to migrate to the site of injury or infection, but in an allergic reaction, too much histamine is released, and it has counter-productive effects.

A natural chemical in the body, which causes an allergic reaction. For example, when a mosquito bites, its saliva instigates a release of histamine, which causes an annoying itch.

The defense substance responsible for most inflammation. It is synthesized from the amino acid histidine and is secreted by mast cells, basophils, and blood platelets. It stimulates vasodilation, capillary permeability, muscle contraction of the bronchioles, secretions of a number of glands, and attracts eosinophils, the white blood cells that are capable of moderating the inflammation. Mast cell histamine release is what usually causes allergies.

A vasoactive amine that causes vasodilation and increased capillary permeability; stored in the granules of mast cells, basophils, and platelets; release may be triggered by immune or non-immune stimuli.

a body chemical that's released when your immune system attacks a perceived invader (allergen). Histamine causes allergy and asthma signs and symptoms, such as narrowing of the airways, mucus secretion, wheezing, coughing, and itchy, runny nose.

a molecule which is released from mast cells during inflammation. It makes blood vessels more permeable.

Powerful molecule produced by mast cells and basophils, that is responsible for an army of unpleasant effects seen in allergy; it causes contraction of smooth muscle and dilation of capillaries and increases the heart rate, among other actions.

Substance released from mast cells during an allergic reaction. It causes itching, sneezing, increased mucous production, and nasal congestion. Antihistamine drugs help to block the effects of histamine.

A natural chemical in the body that is released by certain cells during an allergic reaction. It is responsible for a lot of the swelling and itching that occurs.

A chemical in certain body cells, which contributes to inflammation and causes itching, swelling, sneezing and other allergic symptoms

A substance naturally produced by the body. Amongst other things, it triggers acid production in the stomach by binding to H2 receptors.

amine formed from histidine that stimulates gastric secretions and dilates blood vessels; released by the humane immune system during allergic reactions

a chemical health hazard that causes scombroid poisoning

a neurotransmitter in the central nervous system and an important modulator of gastric acid secretion, vasomotor control, inflammation, and allergic reactions

A chemical released via the body's immune system in response to allergens.

Signal substance from mast cells (see below) in airways, skin, intestinal wall, etc., and which is liberated (released) from the mast cells during an allergic reaction. Causes airway constriction and acute inflammation with rubor (reddening) and edema (swelling).

(his-ta-mean) - a chemical that is made by mast cells during an allergic reaction.

Histamine is a compound made by the body. It is an amine, which is a type of protein that stimulates gastric secretions and dilates blood vessels. It is released by the human immune system during allergic reactions.

Subtype one is a proinflammatory immune system modulator released during inflammatory and allergic processes. Subtype 2 is a chemical messenger that tells the proton pumps in the stomach to release stomach acid.

Mast cells release this chemical that stimulates inflammation. Mast cells counts are normally raised in a patient with IC, which would explain some to the inflammation found within the bladder.

a physiologically active depressor amine used as a powerful stimulant of gastric secretion, constrictor of bronchial smooth muscle, and vasodilator.

A compound found throughout the body, but in highest concentrations in the white blood cell types that are active in inflammation and allergy responses. Release of histamine and its effects on tissues are responsible for some of the symptoms of allergic reactions.

A naturally occurring substance in the body that causes allergic reactions (redness, itching, and swelling) of the nose and eyes — This reaction can also occur in the lung, causing the airways to narrow.

A substance which is a powerful stimulant of gastric acid secretion, causes constriction of the bronchial smooth muscles of the airway, and causes dilation of the capillaries and arterioles, resulting in a fall in blood pressure.

A chemical released from all the cells in your body when you have an allergic reaction.

Molecule released especially during an allergic response that causes smooth muscle contraction, inflammation, mucus secretion, and other allergy symptoms

Allergic people produce this potent inflammatory chemical when they come into contact with the aggravating substance, such as pollen, animal dander or dust mites. Triggers most of the symptoms commonly associated with allergies.

One of a number of body substances released by mast cells that cause allergic symptoms.

A small molecule found in some tissue cells that, when released, acts to produce a number of immunologic phenomena; a substance that will promote shock.

A hormone that acts on histamine receptors around the body, including those implicated in itch, sneezing and nasal discharge

a chemical released by cells of the immune system during an allergic reaction. Histamine causes many of the symptoms of allergy, such as itching, redness and swelling. Medications called antihistamines block the action of this chemical and prevent or reverse the signs and symptoms of an allergic reaction.

A chemical made in the body that is involved in inflammation (swelling, heat, pain and redness associated with damage to the tissues of the body), particularly during allergic reactions. Histamine causes blood vessel walls to relax, which increases the blood supply to the damaged tissue (making it red) and allows more fluid to move from the bloodstream into the tissue (making it swell). Antihistamines, used to treat allergies, block the effects of histamine.

An inflammatory substance produced by the body that is responsible for causing allergy symptoms.

a natural substance released in the human body during an allergic reaction. Histamine is the main cause of nasal allergy symptoms.

Inflammatory mediator stored in mast cell, platelets and other tissues that causes vasodilatation and increased vascular permeability.

A substance released by the immune system after exposure to an allergen, causing the enlargement of nearby blood vessels as well as nasal redness, congestion, swelling, itching, and excess mucus production.

A natural compound, which functions in the human body as a tissue hormone and neurotransmitter. Histamine plays a pivotal role in allergic reactions.

a chemical present in cells throughout the body that is released during an allergic reaction and one of the substances responsible for the symptoms of inflammation.

A neurotransmitter (in the brain; in the body, histamine initiates an allergic reaction).

The chemical released in your body during an allergic response is called histamine.

an amine present in many tissues, release of which can cause dilatation of the capillary blood vessels, flushing and other effects

A chemical released during the inþammatory response that increases capillary blood þow in the affected area, causing heat and redness.

Substance that plays a major role in many allergic reactions. Histamine dilates blood vessels and makes the vessel walls abnormally permeable.

A chemical released by basophils and mast cells that causes nearby tissues to become swollen and inflamed.

a white crystalline compound involved in immune responses (hormone or chemical transmitter). It regulates production of stomach acid and is the main cause of allergic reactions. [C5H9N3

One of the chemical substances involved in the inflammatory reaction and which is responsible for certain allergic symptoms.

a substance produced by the body during an allergic reaction.

a chemical in some cells of the body that is released during allergic reactions, causing inflammation; also causes production of acid in the stomach and narrowing of the airways

A chemical compound formed by the bacterial decomposition of seafood.

(hiss; tah meen) • A substance released within a damaged tissue by a type of white blood cell. Histamines are responsible for aspects of allergice reactions, including the increased vascular permeability that leads to edema (swelling).

a protein involved in triggering stomach acid production; it is released by the ECL cell and signals the parietal cell to begin secreting acid

a substance which suppresses the body's natural immune response to an antigen.

A chemical found in most body tissues that forms part of their defense mechanisms

A naturally occurring substance that is released by the immune system after being exposed to an allergen. Histamine is responsible for many of the symptoms of an allergy.

a compound that is found in many animal tissues or made synthetically. Histamine is probably responsible for the dilation and increased permeability of blood vessels which play a major role in allergic reactions.

the chemical your body produces when you're having an allergic reaction.

Potent pharmacological agent acting through receptors in smooth muscle and in secretory systems. Responsible for the symptoms of anaphylaxis (allergy).

a substance found mostly in the stores in Mast cells. It is released in response to antigens binding specifically to antibodies on their surface and causes the surrounding blood vessels to dilate and contraction of smooth muscle (eg. in the lungs). It normal circumstances histamine causes local inflammation to help fight infection but the same reaction also occurs in allergic conditions such as asthma and hay fever.

A mediator released by mast cells and basophils that causes dilation of blood vessels, increased secretion of acid by the stomach, smooth muscle constriction, and mucus production, tissue swelling, and itching.

A chemical transmitter that is involved in inflammation, particularly inflammation related to an allergic reaction.

Chemical in the body tissues that constricts the smooth muscle surrounding bronchial tubes, dilates small blood vessels, allows leakage of fluid to form itching skin and hives and increases secretion of acid in stomach.

one of the substances released into the tissues during an allergic reaction.

A chemical released by the immune system that acts on various body tissues. It has the effect of constricting the smooth bronchial tube muscles, dilating small blood vessels, allowing fluid to leak from various tissues, and increasing the secretion of stomach acid.

Chemical which, when released from mast cells, cause vasodilation and an increase in permeability of blood vessel walls. These effects, in turn cause the familiar symptoms of allergy including tearing eyes and running nose. Histamine can also cause other symptoms: when released in the lung histamine causes airways to swell shut in an attempt to close the door on offending allergens and keep them out. Unfortunately, the ultimate result of this response is the wheezing and difficulty in breathing seen in people with asthma - another occasionally deadly allergic complication which kills 4000 Americans yearly.

substance released when cells are injured; results in vasodilatation, increased permeability of blood vessels and bronchiole constriction

a chemical messenger produced by many cells in the body that causes dilation of blood vessels, contraction of smooth muscle around airways in the lungs, increased secretion of stomach acid, and mucus production.

A hormone transmitter involved in local immune response regulating stomach acid production and in allergic reactions.

The chemical released by stimulated mast cells or basophils to initiate or enhance an inflammatory response.

A chemical released into the body when an allergic reaction occurs. Itching is one common symptom.

a chemical present in many animal tissues, but particularly in the granules of mast cells and basophils. It is released during allergic reactions and dilates capillaries (causing vascular permeability and a drop in blood pressure) and causes bronchial constriction (closing of the airways).

Chemical produced by body creating allergic reaction and inflammation.

A naturally occurring substance that is released by the immune system after being exposed to an allergen. When you inhale an allergen, mast cells located in the nose and sinus membranes release histamine. Histamine then attaches to receptors on nearby blood vessels, causing them to enlarge (dilate). Histamine also binds to other receptors located in nasal tissues, causing redness, swelling, itching and changes in the secretions.

A chemical produced by the cells of the skin, nasal and respiratory passages, the stomach and other areas. Histamines aid digestion by triggering stomach acid secretion. In response to pollen or other allergens, they can also cause inflammation, hives, itching, excessive mucus and constriction of the airways.

Substance released by mast cells; important in the inflammatory response. Triggers vascular changes, including dilation of the blood vessels. A chemical released during an allergic reaction.

A hormone released by the body during allergic reaction that stimulates gastric secretion and causes dilation of capillaries, constriction of bronchial smooth muscle, and decreased blood pressure.

A natural chemical that is released by Mast Cells in the body initiating an allergic reaction which leads to inflammation in affected parts of the body.

Paracrine amine released during stimulation of gastric acid secretion. Also found in mast cells in skin; released as part of inflammatory response to injury.

Histamine is a vasoactive amine stored in mast cell granules. Histamine released by antigen binding to IgE molecules on mast cells causes dilation of local blood vessels and smooth muscle contraction, producing some of the symptoms of immediate hypersensitivity reactions. Antihistamines are drugs that counter histamine action.

Histamine is a substance your body injects into your bloodstream to help you stay alert. However, it is often triggered by allergens. It causes fluid to be released into the skin (which causes swelling and hives), and when released into the sinuses can cause a runny nose and watery eyes.

A chemical in the body tissues, produced by the breakdown of histidine. It is released in allergic reactions and causes widening of capillaries, decreased blood pressure, increased release of gastric juice, fluid leakage forming itchy skin and hives, and tightening of smooth muscles of the bronchial tube and uterus.

Histamine is a biogenic amine chemical involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. New evidence also indicates that histamine plays a role in chemotaxis of white blood cells.