Influence of anesthetics on endogenous and recombinantly expressed G protein-coupled receptors in the Xenopus oocyte

1. The oocyte of the African clawed toad (Xenopus laevis) offers a reliable , sensitive and disease resistant system to investigate recombinantly and e ndogenously expressed Ca2+ signaling G protein-coupled receptors and their intracellular signaling pathways. 2. To study receptor induced Ca2+ release , two-electrode voltage clamping can quantify a Ca2+-activated transmembran e Cl- current. Intracellular steps of the signaling pathway can be inhibite d by injections of EDTA or heparin into the oocyte, Components of the intra cellular pathway can be activated directly by GTP gamma S or IP3 injection. 3. We have investigated the effects of volatile, local and i.v. anesthetic s on the signaling properties of the endogenous lysophosphatidate receptor and on mammalian receptors expressed recombinantly by intracellular injecti on of the encoding mRNA or cDNA. A number of receptors are sensitive to the se anesthetics. Anesthetics interact with muscarinic, thromboxane A(2) and lysophosphatidate signaling. 4. Investigations of the intracellular pathway s revealed that the receptor or the receptor-G protein coupling is affected primarily and that mechanisms further downstream are not influenced by the various types of anesthetics. (C) 1998 Published by Elsevier Science Irela nd Ltd. All rights reserved.