Amino acid residues involved in agonist binding and its linking to channel gating, proximal to transmembrane domain of 5-HT3A receptor for halothane modulation.
10.4097/kjae.2009.56.1.66
- Author:
Mi Kyeong KIM
1
;
Kyeong Tae MIN
;
Bon Nyeo KOO
Author Information
1. Department of Anesthesiology and Pain Medicine, Kyung Hee University College of Medicine, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Electrophysiology;
5-HT3A receptor;
5-HT;
Halothane;
Site-directed single mutation;
Xenopus Laevis oocytes
- MeSH:
Anesthetics;
Electrodes;
Electrophysiology;
Halothane;
Ligand-Gated Ion Channels;
Oocytes;
Patch-Clamp Techniques;
Receptors, Serotonin, 5-HT3;
Serotonin;
Xenopus laevis
- From:Korean Journal of Anesthesiology
2009;56(1):66-73
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: The 5-hydroxytryptamine type 3 (5-HT3) receptor is a member of the Cys-loop superfamily of ligand-gated ion channels (LGICs) and modulated by pharmacologic relevant concentrations of volatile anesthetics or n-alcohols like most receptors of LGICs. The goal of this study was to reveal whether the site-directed single mutations of E-106, F-107 and R-222 in 5-HT3 receptor may affect the anesthetic modulation of halothane known as positive modulator. METHODS: The wild-type and mutant receptors, E106D, F107Y, R222F, R222V, were expressed in Xenopus Laevis oocytes and receptor function was assessed using two electrode voltage clamp techniques. RESULTS: E106D, F107Y, R222F, R222V mutant 5-HT3A receptors were functionally expressed. F107Y mutant 5-HT3A receptors displayed decreased sensitivity to 5-HT compared to the wild type 5-HT3A receptor (P < 0.05). Halothane showed positive modulation in both wild and F107Y mutant 5-HT3A receptors but F107Y mutant 5-HT3 receptor showed greater enhancing modulation comparing to wild-type receptor. Meanwhile, R222F and R222V mutant 5-HT3 receptor lost positive modulation with 1 and 2 MAC of halothane. Most interestingly, positive modulation by halothane was converted into negative modulation in E106D mutant 5-HT3A receptor. CONCLUSIONS: The present study implicate the amino acid residues known for agonist binding and linking agonist binding to channel gating might also have important role for anesthetic modulation in 5-HT3A receptor.
