A substance that plays a major role in many allergic reactions, dilating blood vessels and making the vessel walls abnormally permeable. Histamine is part of the body's natural allergic response to substances such as pollens. Antihistamines work by preventing the release of histamine from certain cells (mast cells) thereby blocking the allergi [..]

A substance that has many effects in the body. It is released from some types of white blood cells during allergic reactions. It causes small blood vessels to dilate (widen) and become leaky, which ca [..]

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

2-(1H-imidazol-4-yl)ethan-1-amine, an amine derived from histidine by decarboxylation and released from cells in the immune system as part of an allergic reaction: it is a powerful stimulant of gastri [..]

1913, "amine produced by the decomposition of histidine."

A chemical that is released by the body due to an allergic reaction.

A chemical stored inside mast cells and basophils that is one of the important contributors to allergic reactions. Histamine causes increased vascular permeability and contraction of smooth muscle in [..]

A chemical with a variety of roles in the body. In allergic reactions it is released when mast cells are stimulated. It causes capillaries to become leaky, releasing fluid and white blood cells into t [..]

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

A substance released from certain cells in response to allergens, associated with the development of allergic symptoms, including itchy eyes, sneezing and congestion.

A substance released by the immune system when it is exposed to an allergen. Histamines cause many allergy symptoms.

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 histam [..]

Histamine is a substance in the body that's released during an allergic reaction. It can cause allergy symptoms that affect the eyes, nose, throat, skin, digestive system, and lungs. When histami [..]

Histamine is an important chemical in the process of inflammation. It is released from mast cells and causes dilation of blood vessels and activation of most other steps in 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 i [..]

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 Neurot [..]

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 neurot [..]

A physiologically active amine, C5H9N3, found in plant and animal tissue and released from mast cells as part of an allergic reaction in humans. It stimulates gastric secretion and causes dilation of [..]

A key chemical in the body's immune defense. Released during allergic reactions, histamine causes swelling, itching, rash, sneezing, and other symptoms.

a compound found in mammalian tissues that causes stretching of capillaries, contraction of smooth muscle, and stimulation of gastric acid secretions; released during allergic reactions.

A highly active natural chemical released from the mast cells as a result of an allergic reaction, and a major contributor to the symptoms of allergy. Back to top

a chemical released during an allergic reaction that causes symptoms, such as rash or excess mucus in the respiratory system

A substance occurring in mast cells in the body.  In an allergic reaction, it is one of the chemicals released, which causes the symptoms of allergy including itching, sneezing, wheezing, and runny no [..]

This amine is released quickly from mast cell granules in response to antigen stimulation resulting in local increased blood flow and vascular leakage promoting the influx of immune cells. Read about [..]

Histamine is a chemical present in cells throughout the body that is released during an allergic reaction. Histamine is one of the substances responsible for the symptoms on inflammation and is the major reason for running of the nose, sneezing, and itching in allergic rhinitis. It also stimulates production of acid by the stomach and narrows the b [..]

a simple, nitrogenous molecule involved in initiating localised inflammatory responses.

Histamine is a chemical present in cells throughout the body that is released during an allergic reaction. Histamine is one of the substances responsible for the symptoms on inflammation and is the major reason for running of the nose, sneezing, and itching in allergic rhinitis. It also stimulates production of acid by the stomach and narrows the b [..]

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.

Is a biological substance produced as part of an allergic reaction that can cause swelling of body parts and restricted airways. It causes irritation, eye watering and running nose. Hay fever is a common manifestation of histamine in action.

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 itching [..]

Histamine is a naturally-occurring body chemical involved in immune response and food digestion. It is made in the white bloods cells, which are largely responsible for fighting infection. When histam [..]

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 lungs 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 ti [..]

a chemical that stimulates the autonomous nervous system, secretion of gastric juices, and dilation of capillaries

A chemical your body produces in response to an allergic reaction. It also mediates several other biological activities in the body. There are 4 histamine receptors (H1-4) that are found on cells. Antihistamines, like Benadryl®, block some of the histamine receptors, and relieve symptoms of the allergic reaction.