What is histamine in pharmacology?

Histamine is an endogenous substance that is widely distributed throughout the body. The two principal sites of storage for histamine are the mast cells in tissue and the basophils in blood. ++ The action of histamine is mediated through at least two receptors, H1 and H2.

How do antihistamines work pharmacology?

Antihistamines suppress the histamine-induced wheal response (swelling) and flare response (vasodilation) by blocking the binding of histamine to its receptors or reducing histamine receptor activity on nerves, vascular smooth muscle, glandular cells, endothelium, and mast cells.

What is histamine in medicinal chemistry?

Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus.

What is the classification of histamine?

Histamine is classified as an amine because it is based on the structure of ammonia and is formed through decarboxylation of the amino acid histidine. Histamine is an autacoid, which means it acts similarly to a local hormone, near its site of synthesis.

What is the action of histamine?

Histamine regulates a plethora of pathophysiological and physiological processes, such as secretion of gastric acid, inflammation, and the regulation of vasodilatation and bronchoconstriction (29, 30). In addition, it can also serve as a neurotransmitter (31).

What is the purpose of histamines?

They’re chemicals your immune system makes. Histamines act like bouncers at a club. They help your body get rid of something that’s bothering you — in this case, an allergy trigger, or “allergen.” Histamines start the process that hustles those allergens out of your body or off your skin.

What is the mechanism of action for histamine?

Histamine acts directly on the blood vessels to dilate arteries and capillaries; this action is mediated by both H 1- and H 2-receptors.

What is the function of antihistamine?

Antihistamines are used to relieve or prevent the symptoms of hay fever and other types of allergy. They work by preventing the effects of a substance called histamine, which is produced by the body. Histamine can cause itching, sneezing, runny nose, and watery eyes.

What is histamine function?

What is the role of histamine?

Histamine is a central mediator released from mast cells through allergic reactions. Histamine plays a role in airway obstruction via smooth muscle contraction, bronchial secretion, and airway mucosal edema.

What are the 4 histamine receptors?

The biological impact of histamine follow their interaction with four types histamine receptors, H1R, H2R, H3R, and H4R, all of which belong to the G protein coupled receptor family (8, 16–20).