Biogenic amine receptor

Biogenic amine receptors are "cell surface proteins that bind biogenic amines with high affinity and regulate intracellular signals which influence the behavior of cells. Biogenic amine is a chemically imprecise term which, by convention, includes the catecholamines epinephrine, norepinephrine, and dopamine, the indoleamine serotonin, the imidazolamine histamine, and compounds closely related to each of these."

Biogenic amines are a "group of naturally occurring amines derived by enzymatic decarboxylation of the natural amino acids. Many have powerful physiological effects (e.g., histamine, serotonin, epinephrine, tyramine). Those derived from aromatic amino acids, and also their synthetic analogs (e.g., amphetamine), are of use in pharmacology." The neurotransmitter acetylcholine is also a biogenic amine.

Classification

Catecholamine receptors

Catecholamines are epinephrine, norepinephrine, dopamine. They are derived from the non-essential amino acid tyrosine which is found in casein in mild and cheese.

Catecholamine receptors are "cell surface proteins that bind catecholamines with high affinity and trigger intracellular changes which influence the behavior of cells. The catecholamine messengers epinephrine, norepinephrine, and dopamine are synthesized from tyrosine by a common biosynthetic pathway."

Adrenergic receptors

alpha-Adrenergic Receptors

alpha-1 Adrenergic receptors

Alpha-1 adrenergic receptors are a "subclass of alpha-adrenergic receptors (Receptors, Adrenergic, alpha). Alpha-1 Adrenergic receptors can be pharmacologically discriminated, e.g., by their high affinity for the agonist phenylephrine and the antagonist prazosin. They are widespread, with clinically important concentrations in the liver, the heart, vascular, intestinal, and genitourinary smooth muscle, and the central and peripheral nervous systems." Their functions include vasoconstriction.

Agonists, such as phenylephrine, are used to treat nasal congestion by causing vasoconstriction.

Antagonists, such as prazosin, are used to treat hypertension by blocking vasoconstriction.

alpha-2 Adrenergic receptors

Alpha-2 adrenergic receptors are a "subclass of alpha-adrenergic receptors (Receptors, adrenergic, alpha). Alpha-2 Adrenergic receptors can be pharmacologically discriminated, e.g., by their high affinity for the agonist clonidine and the antagonist yohimbine. They are found on pancreatic beta cells, platelets, and vascular smooth muscle, as well as both pre- and postsynaptically in the central and peripheral nervous systems."

Agonists, such as clonidine, are used to treat hypertension.

Antagonists, such as yohimbine, are used to treat erectile dysfunction.

beta-Adrenergic Receptors

beta-1 Adrenergic receptors

Beta-1 adrenergic receptors are a "subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-1 adrenergic receptors are equally sensitive to epinephrine and norepinephrine and bind the agonist dobutamine and the antagonist metoprolol with high affinity. They are found in the heart, juxtaglomerular cells, and in the central and peripheral nervous systems."

Agonists, such as dobutamine, are used to treat circulatory shock by increasing heart contractility.

Antagonists, such as metoprolol, are used to treat hypertension and tachyarrythmias.

beta-2 Adrenergic receptors

Beta-2 adrenergic receptors are a "subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-2 Adrenergic receptors are more sensitive to epinephrine than to norepinephrine and have a high affinity for the agonist terbutaline. They are widespread, with clinically important roles in skeletal muscle, liver, and vascular, bronchial, gastrointestinal, and genitourinary smooth muscle."

Agonists, such as terbutaline, are used to treat asthma by preventing bronchoconstriction.

beta-3 Adrenergic receptors

Beta-3 adrenergic receptors are a "subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-3 adrenergic receptors are the predominant beta-adrenergic receptor type expressed in white and brown adipocytes and are involved in modulating energy metabolism and thermogenesis."

Dopamine receptors

Dopamine is "one of the catecholamine neurotransmitters in the brain. It is derived from tyrosine and is the precursor to norepinephrine and epinephrine. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement."

Dopamine receptors are "cell-surface proteins that bind dopamine with high affinity and trigger intracellular changes influencing the behavior of cells."

D₁-like receptors

These receptors stimulate adenylate cyclase.

D₂-like receptors

These receptors inhibit adenylate cyclase.

Dopamine D2 receptors

Agonists, such as metoclopramide, are used as an antiemetic.

Antagonists, such as risperidone and haloperidol, are used to treat schizophrenia.

Histamine receptors

Histamine is 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."

Histamine receptors are "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."

Histamine H1 receptors

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."

Antagonists, such as chorpheniramine, are used to treat allergic rhinitis.

Histamine H2 receptors

Histamine H2 receptors "act via G-proteins to stimulate adenylate cyclase. 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."

Antagonists, such as ranitidine, are used to treat gastrointestinal disorder such as peptic ulcer disease and gastroesophageal reflux disease that are due to hyperacidity.

Histamine H3 receptors

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.

Serotonin receptors

Serotonin is 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."

Serotonin receptors are "cell-surface proteins that bind serotonin and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action."

Serotonin 5-HT1 receptors

Serotonin 5-HT1 receptors are in the central nervous system.

Agonists of serotonin 5-HT_1D, such as sumatriptan, are used to treat migraine headaches.

Serotonin 5-HT2 receptors

Antagonists, such as risperidone, are used to treat schizophrenia. Antagonists, such as fluoxetine, are used to treat depression.

Serotonin 5-HT3 receptors

Serotonin 5-HT3 receptors stimulate gastrointestinal motility.

Antagonists, such as ondansetron, are used as an antiemetic for chemotherapy. Antagonists, such as alosetron, are to treat diarrhea-predominant irritable bowel syndrome.

Serotonin 5-HT4 receptors

Serotonin 5-HT4 receptors stimulate gastrointestinal motility.

Agonists, such as tegaserod, are used to treat constipation-predominant irritable bowel syndrome.