Alcohol effects on the 5-HT3 ligand-gated ion channel

1. Alcohols and volatile anesthetics have both potentiating and channel blo cking effects on members of the nicotinic ACh-like subfamily of ligand-gate d ion channels. 2. The alcohol and anesthetic sensitivity of the 5-HT3 rece ptor, a member of this receptor subfamily, has been examined extensively by several laboratories. 3. Alcohols and volatile anesthetics potentiate rece ptor function. 4. This potentiation is characterized by an increase in the apparent potency with which agonists activate the receptor, and an apparent stabilization and favoring of the open channel state. 5. Long-chain alcoho ls and trichloroethanol also inhibit channel function, perhaps through a ch annel blocking mechanism similar to that seen at the nACh receptor. 6. Stud ies of the relationship between receptor structure and alcohol and anesthet ic effects are just beginning, but some clues from other members of this su bfamily of ligand-gated channels may help to pinpoint areas of the receptor that are important for alcohol effects. (C) 1998 Published by Elsevier Sci ence Ireland Ltd. All rights reserved.