The histamine receptors are a class of
G protein–coupled receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...
s which bind
histamine as their primary
endogenous ligand
In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...
.
There are four known histamine receptors:
*
H1 receptor
*
H2 receptor
*
H3 receptor
*
H4 receptor
Comparison
There are several
splice variants of H
3 present in various
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
. Though all of the receptors are
7-transmembrane g protein coupled receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...
s, H
1 and H
2 are quite different from H
3 and H
4 in their activities. H
1 causes an increase in
PIP2 hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolys ...
, H2 stimulates
gastric acid secretion, and H3 mediates
feedback inhibition of histamine.
References
External links
*
Holger Stark: Histamine Receptors, BIOTREND Reviews No. 01, November 2007The Histamine Receptor
*
{{Histaminergics
Integral membrane proteins
Histamine receptors