Korean J Anesthesiol.  2000 Dec;39(6):854-859. 10.4097/kjae.2000.39.6.854.

Effects of Halothane, Enflurane or Isoflurane on the m1 or m3 Muscarinic Receptor Expressed in Xenopus Oocytes

• Do SH

• KMID: 2091577
• DOI: http://doi.org/10.4097/kjae.2000.39.6.854

Abstract

BACKGROUND: Muscarinic receptors are distributed abundantly in the central nervous system and peripheral visceral organs, and have a close relationship with anesthesia. We investigated the effects of halothane, enflurane or isoflurane on m1 or m3 muscarinic signaling. METHODS: Using two electrode voltage clamps, Ca2+ -activated Cl- currents (ICl(Ca)) were measured in Xenopus oocytes injected with an m1 or m3 receptor mRNA. ICl(Ca) was induced with the application of acetyl beta-methylcholine with or without exposure to volatile anesthetics. RESULTS: Halothane depressed the m1 and m3 receptor function significantly (m1; 0.49 +/- 0.17 microampere -> 0.1 +/- 0.05 microampere, m3; 0.74 +/- 0.2 -> 0.23 +/- 0.06 microampere, P < 0.05). Enflurane also decreased signaling through both receptors significantly (m1; 0.49 +/- 0.1 -> 0.15 +/- 0.04 microampere, m3; 0.95 +/- 0.34 -> 0.19 +/- 0.05 microampere, P < 0.05). However, while isoflurane depressed m3 signaling significantly (0.82 +/- 0.19 -> 0.3 +/- 0.09 microampere, P < 0.05), it did not cause significant changes in ICl(Ca) through the m1 receptor (0.29 +/- 0.05 vs 0.23 +/- 0.09 microampere, P > 0.5). From a concentration-response curve, enflurane decreased m1 and m3 signaling dose-dependently. CONCLUSIONS: Our data suggests that m1 and m3 muscarinic receptors were depressed by halothane, enflurane or isoglurane except for the fact that the m1 receptor was not affected by isoflurane.

Keyword

Anesthetics, volatile: enflurane; halothane; isoflurane; Cells: Xenopus oocytes; Receptors: muscarinic

MeSH Terms

Anesthesia
Anesthetics
Central Nervous System
Electrodes
Enflurane*
Halothane*
Isoflurane*
Oocytes*
Receptors, Muscarinic*
RNA, Messenger
Xenopus*
Anesthetics
Enflurane
Halothane
Isoflurane
RNA, Messenger
Receptors, Muscarinic