Activation kinetics and single channel properties of recombinant alpha1beta2gamma2L GABA(A) receptor channels.
Recombinant alpha1beta2gamma2L GABA(A) receptor channels, transiently expressed in HEK 293 cells, were investigated using the patch-clamp technique in combination with a device for ultra-fast solution exchange. The dose-response relationship revealed an EC50 of 11.6 +/- 0.9 microM and saturated with 3 mM GABA. The slope between 0.001 and 0.01 mM GABA was 2.2 +/- 0.4, indicating at least three binding sites for GABA. The rise time decreased from about 120 ms at 0.001 mM GABA to about 0.8 ms at 10 mM GABA. Single channel openings were grouped in bursts with an average duration of 10.3 +/- 3.0 ms. More than 95% of the current was represented by a single channel slope conductance of about 29 pS.
Jahn
K
K
Department of Neurology, Technical University Munich, Germany.
Hertle
I
I
Bufler
J
J
Adelsberger
H
H
Pestel
E
E
Zieglgänsberger
W
W
Dudel
J
J
Franke
C
C
D002460:Cell Line; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D046911:Macromolecular Substances; D011963:Receptors, GABA-A / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D013997:Time Factors; D014162:Transfection; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D046911:Macromolecular Substances; D011963:Receptors, GABA-A; D011993:Recombinant Fusion Proteins; D005680:gamma-Aminobutyric Acid