Absteric modulation receptors: focus on alcohols and ;arzaesthetic agents

Both functional and structural information indicates that the 5-HT, receptor is an ion channel, and hence belongs to the transmitter-gated ion channel superfamily (for review see Ref. 1). In common with all thr, other members of this superfamily (for example, nicotinic acetylcholine receptors), the 5-HT, receptor complex is likely to be comprised of five subunitsl, although to date only one subunit (5-HT,-A receptor subunit), and an alternatively spliced variant (5-HT,-As receptor subunit”), has been identified in various species (moused? rats, humantJ). It remains open to debate whether additional 5-HT, receptor subunits exist, since the homomeric 5-l-ITS-A alld 5-HT3-As receptor are functional although they do not display all of the characteristics of native 5-HT, receptors (for reviews see Refs El, 9). The 5-HT, receptor has received considerable attention over recent years and is now known to play a key role in emesis and may also be reievant to some of the symptoms associated with CNS disordersH,ll’. While the majority of pharmacological research concerning this receptor centres on the recognition site for 5-HT, it is becoming increasingly clear that the 5-HT, receptor compl!,ji-, like other members of this sqerfamily, possesses additional @armacologically distinct recog:&ion &es by which the function of the receptor can be allosterically modulated.