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histamine H3 receptor (G protein-coupled receptor 97, HH3R, HRH3, GPCR97)
Function:
- mediation of histamine signals in CNS & peripheral nervous system
- signals through inhibition of adenylate cyclase
- high constitutive activity
- agonist stimulation of isoform 3 neither modifies adenylate cyclase activity nor induced intracellular Ca+2 mobilization
- does not bind to cimetidine & tripolidine
- modest affinity for thioperamide, imetit, N-alpha-methylhistamine & R(-)-alpha-methylhistamine
- isoform 4 is unable to bind to iodoproxyfan; isoforms 1 & 3 bind it with high affinity
Structure:
- belongs to the G-protein coupled receptor 1 family
Compartment: cell membrane
Alternative splicing: named isoforms=7
Expression:
- expressed predominantly in the CNS
- greatest expression in thalamus & caudate nucleus
- various isoforms are mainly coexpressed in brain
- relative expression level varies in a region-specific manner
- isoform 3 & isoform 7 are highly expressed in the thalamus, caudate nucleus & cerebellum
- isoforms 5 & 6 show a poor expression
- isoform 5 & 6 show a high expression in the amygdala, substantia nigra, cerebral cortex & hypothalamus
- isoform 7 is not found in hypothalamus or substantia nigra
Pathology:
- mutations associated with Shy-Drager syndrome
General
histamine receptor
Properties
SIZE: entity length = 445 aa
MW = 49 kD
COMPARTMENT: cellular membrane
MOTIF: exoplasmic domain {1-39}
MOTIF: N-glycosylation site {N11}
alanine-rich region {20-23}
MOTIF: alanine residue (SEVERAL)
transmembrane domain {40-60}
cytoplasmic loop {61-70}
transmembrane domain {71-91}
exoplasmic loop {92-108}
transmembrane domain {109-129}
cytoplasmic loop {130-156}
transmembrane domain {157-177}
exoplasmic loop {178-196}
transmembrane domain {197-217}
cytoplasmic loop {218-359}
MOTIF: proline-rich region
SITE: 250-256
MOTIF: proline residue (SEVERAL)
glycine-rich region {292-298}
transmembrane domain {360-380}
exoplasmic loop {381-395}
transmembrane domain {396-416}
cytoplasmic domain {417-445}
Database Correlations
OMIM correlations
UniProt Q9Y5N1
Pfam PF00001
References
- Bekkers JM
Enhancement by histamine of NMDA-mediated synaptic transmission
in the hippocampus.
Science 261:104 1993
PMID: 8391168
- UniProt :accession Q9Y5N1
- Wiedemann P et al.
Structure of the human histamine H3 receptor gene (HRH3) and
identification of naturally occurring variations.
J Neural Transm. 2002 Apr;109(4):443-53.
PMID: 11956964