Histamine H3 Receptors

Histamine H3 receptors are Gαi/o-protein-coupled receptors expressed at high levels on histaminergic neurons in the CNS, particularly in the basal ganglia, cortex and hippocampus. H3 receptors are thought to function as presynaptic autoreceptors.

Products
Background
Literature
Gene Data

Agonists

Cat No Product Name / Activity
3545 Histamine dihydrochloride
Endogenous histamine receptor agonist
0729 Imetit dihydrobromide
Standard H3 and H4 agonist (H3 > H4)
0932 Immepip dihydrobromide
Standard H3 agonist. Also H4 agonist
2315 Immethridine dihydrobromide
Potent H3 agonist, highly selective over H4
0569 (R)-(-)-α-Methylhistamine dihydrobromide
Potent, standard H3 agonist
0572 (S)-(+)-α-Methylhistamine dihydrobromide
H3 agonist, less active enantiomer
0573 Nα-Methylhistamine dihydrochloride
Non-selective H3 agonist
2477 Proxyfan oxalate
High affinity H3 ligand

Antagonists

Cat No Product Name / Activity
4697 A 331440 dihydrochloride
Selective H3 antagonist
3743 BF 2649 hydrochloride
H3 receptor inverse agonist/antagonist
2211 Carcinine ditrifluoroacetate
Highly selective H3 antagonist
0752 Clobenpropit dihydrobromide
Highly potent H3 antagonist and H4 partial agonist
2409 Conessine
Potent and selective H3 receptor antagonist
2419 GT 2016
Selective H3 antagonist
1858 Impentamine dihydrobromide
Selective H3 antagonist
0779 Iodophenpropit dihydrobromide
Potent, selective H3 antagonist
4019 JNJ 10181457 dihydrochloride
H3 antagonist
4020 JNJ 5207852 dihydrochloride
High affinity H3 receptor antagonist
2034 ROS 234 dioxalate
Potent H3 antagonist
4441 SEN 12333
Histamine H3 antagonist; α7 nAChR agonist
0644 Thioperamide
H3 antagonist and H4 inverse agonist
2493 VUF 5681 dihydrobromide
Potent H3 receptor silent antagonist

Ligand-sets

Cat No Product Name / Activity
1876 Histamine H3 Receptor Tocriset™
Selection of 5 histamine H3 receptor ligands (Cat. Nos. 0729, 0569, 0752, 0779 and 0644)

Histamine H3 receptors are Gαi/o-protein-coupled receptors first cloned in 1999. H3 receptors are expressed at high levels on histaminergic neurons in the central nervous system, particularly in the basal ganglia, cortex, hippocampus and strial area. They are expressed in the periphery at lower densities in the gastrointestinal, bronchial and cardiovascular systems.

H3 receptors are thought to function as presynaptic autoreceptors and their activation stimulates the negative feedback mechanism that reduces central histaminergic activity. These receptors have displayed heterogeneity in binding and functional studies, suggesting multiple subtypes. In rats, three H3 receptor subtypes have been identified and they all vary in the length of the third extracellular loop, have distinct CNS localization and differentially couple to adenylyl cyclase and MAPK signaling pathways.

H3 receptors have multiple functions including roles in cognition, sleep-wake status, energy homeostasis regulation and inflammation. Activation of these receptors can inhibit histamine, dopamine, serotonin, noradrenalin and acetylcholine release and they participate in control of neurogenic inflammation through local-neuron feedback loops. Furthermore, H3 receptor activation increases antigen-presenting cell capacity.

H3 receptors are thought to have pathophysiological relevance and are involved in cognitive impairment, seizures and possibly metabolic syndrome. The human gene encoding this receptor is localized to chromosome 20q13.33.

External sources of pharmacological information for Histamine H3 Receptors :

Literature for Histamine H3 Receptors

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Histamine H3 Receptor Gene Data

Species Gene Symbol Gene Accession No. Protein Accession No.
Human HRH3 NM_007232 Q9Y5N1
Mouse Hrh3 NM_133849 P58406
Rat Hrh3 NM_053506 Q9QYN8