PT  - JOURNAL ARTICLE
AU  - Markus W. Hollmann
AU  - Kathrin S. Wieczorek
AU  - Andreas Berger
AU  - Marcel E. Durieux
TI  - Local Anesthetic Inhibition of G Protein-Coupled Receptor Signaling by Interference with Gα<sub>q</sub> Protein Function
AID  - 10.1124/mol.59.2.294
DP  - 2001 Feb 01
TA  - Molecular Pharmacology
PG  - 294--301
VI  - 59
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/59/2/294.short
4100  - http://molpharm.aspetjournals.org/content/59/2/294.full
SO  - Mol Pharmacol2001 Feb 01; 59
AB  - Although local anesthetics are considered primarily Na+ channel blockers, previous studies suggest a common intracellular site of action on different G protein-coupled receptors. In the present study, we characterized this site for the LPA, m1 muscarinic, and trypsin receptor. Xenopus laevis oocytes expressing endogenous LPA and trypsin or recombinant m1 receptors were two-electrode voltage clamped. We studied LPA inhibition in the presence of ropivacaine stereoisomers to determine whether LA act on a protein site. Ropivacaine inhibited LPA signaling in a stereoselective and noncompetitive manner, suggesting a protein interaction. Antisense injection was used to characterize G protein α-subunits involved in mediation of LPA, m1, trypsin, and angiotensin1A receptor signaling. Lidocaine and its analog QX314 were injected into oocytes expressing these receptors to examine a potential role for specific G protein α-subunits as targets for LA. Gαq was shown to be among the primary G protein subunits mediating the LPA, m1, and trypsin receptor signaling, all of which were inhibited to a similar degree by intracellular injected QX314 (424 × 10−6M). Since the angiotensin1A receptor, previously shown not to be affected by LA, was found not to signal via Gαq, but via Gαo and Gα14, the intracellular effect of LA most likely takes place at the Gαq-subunit.