Neurotransmitters and other chemical signalling agents
| HISTAMINE (HA) | ||||
|---|---|---|---|---|
| Precursors: | Histidine | |||
| Synthesising enzymes: | Histidine decarboxylase | |||
| Metabolising enzymes: | Histamine-N-methyl transferase, histaminase, histamine acetylase, diamine oxidase | |||
| Metabolite: | Methylhistamine, imidazolyl acetic acid, N-methyl imidazolyl acetic acid | |||
| Receptor subtypes | Receptor type and second messenger | Cloned? | Agonists | Antagonists |
| H1 | 7TM (couples to Gq/G11, elevates PI turnover) | human: 487aa g-pig: 488aa rat: 486aa |
2-(3-fluorophenyl) histamine, 2-[(3-trifluoromethyl) phenyl] histamine | mepyramine (CAS 59-33-6), triprolidine (CAS 486-12-4) |
| H2 | 7TM (couples to Gs, elevates cAMP) | human: 359aa rat: 358aa |
amthamine (CAS 142437-67-0), impromidine (CAS 55273-05-07) | ranitidine (CAS66357-35-5), tiotidine (CAS 69014-14-8) |
| H3 | 7TM (? -ve coupling to PLC; ?Ca2+) | (R)-alpha- methylhistamine (CAS 6986-90-9), imetit (S-[2-4(5)-imidazolyl]ethylis othiourea) (CAS 102203-18-9) |
clobenpropit, thioperamide (CAS 106243-16-7) | |
Reviews
Hill, S.J. et al. (1997) Pharmacol. Revs. in press (IUPHAR nomenclature recommendations)
Leurs R. et al. (1995) Pharmacol. Ther. 66, 413-463
5-Hydroxytryptamine / Serotonin
Glycine
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