RT Journal Article
SR Electronic
T1 Trichloroethanol Modulation of Recombinant GABA<sub>A</sub>, Glycine and GABA ρ<sub>1</sub> Receptors
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 934
OP 942
VO 284
IS 3
A1 Matthew D. Krasowski
A1 Suzanne E. Finn
A1 Qing Ye
A1 Neil L. Harrison
YR 1998
UL http://jpet.aspetjournals.org/content/284/3/934.abstract
AB The actions of 2,2,2,-trichloroethanol were studied on agonist-activated Cl− currents in γ-aminobutyric acid type A (GABAA), glycine and GABA ρ1 receptors by use of the whole-cell patch-clamp technique. Recombinant wild-type and mutant receptor subunits were transiently expressed in human embryonic kidney (HEK) 293 cells. Trichloroethanol enhanced currents elicited by submaximal (EC20) agonist concentrations at GABAA α2β1 receptors and glycine α1 homomeric receptors in a reversible, concentration-dependent manner. Trichloroethanol, at concentrations of ≤2 mM, did not significantly alter the magnitude of submaximal GABA currents at GABA ρ1 receptors, whereas higher concentrations inhibited submaximal GABA currents. Recent work has identified residues within putative transmembrane domains 2 and 3 as critical for positive modulation of GABAA and glycine receptors by n-alkanols and volatile ether anesthetics. Submaximal glycine currents at receptors containing either of two specific mutations within the glycine receptor α1 subunit (S267I and A288W) were not enhanced by low concentrations of trichloroethanol and were inhibited by higher concentrations of trichloroethanol. In the GABAAα2β1 receptor, a specific mutation within transmembrane domain 3 of the β1 subunit (M286W) also abolished positive modulation by trichloroethanol. Mutations within the GABAAα2 receptor subunit did not alter positive modulation by TCEt, whereas such mutations ablate positive modulation byn-alkanols and volatile anesthetics. In summary, trichloroethanol modulation of GABAA, glycine and GABA ρ1 receptors shares some, but not all, features in common with the requirements for modulation by n-alkanols and volatile anesthetics. The American Society for Pharmacology and Experimental Therapeutics