Although working basically through the same mechanism, there are several 5-HT1 receptor subtypes (denoted A-F), each encoded by a separate gene. Furthermore each subtype has a somewhat different tissue distribution and binding preference for synthetic 5-HT1agonist and antagonistligands.
5-HT1D acts on the CNS, and affects locomotion and anxiety. It also induces vascular vasoconstriction in the brain. Ergotamine works primarily through the 5-HT1B receptor, since the effect through the 5-HT1D receptor is contrary to the mode of action of ergotamine, i.e. vasoconstriction.
↑Glennon RA, Hong SS, Dukat M, Teitler M, Davis K (1994). "5-(Nonyloxy)tryptamine: a novel high-affinity 5-HT1D beta serotonin receptor agonist". J. Med. Chem. 37 (18): 2828–30. doi:10.1021/jm00044a001. PMID8071931.CS1 maint: Multiple names: authors list (link)