histamine H3 receptor (G protein-coupled receptor 97, HH3R, HRH3, GPCR97)
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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
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
More general terms
References
- ↑ Bekkers JM Enhancement by histamine of NMDA-mediated synaptic transmission in the hippocampus. Science 261:104 1993 PMID: https://www.ncbi.nlm.nih.gov/pubmed/8391168
- ↑ UniProt http://www.uniprot.org/uniprot/Q9Y5N1.html
- ↑ 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: https://www.ncbi.nlm.nih.gov/pubmed/11956964