Modulation by lanthanum ions of gamma-aminobutyric acid(A) receptors of rat cerebellum granule cells in culture: clues on their subunit composition.
Gamma-aminobutyric acid (GABA) activated chloride currents were studied in rat cerebellum granule cells in culture by the whole cell patch-clamp technique. Both the peak and steady state currents were inhibited by 100 microM lanthanum. In the first case, inhibition is due to an increase of the EC50 for GABA. The inhibitory effect of lanthanum on the peak current at 3 microM GABA increased with the cation concentration. A tendency towards the same behavior was found also for the inhibition of the steady state current, at 3 microM GABA, as a function of lanthanum concentration, although inhibition in this case was lower. The comparison of the results with published data about the effects of lanthanum on recombinant GABA(A) receptors likely to occur in granule cells allows suggestions about the receptor types giving, respectively, the peak and the steady state component.
Barilà
B
B
Dipartimento di Fisica dell'Università di Genova, I.N.F.M., Via Dodecaneso 33, 16146, Genova, Italy.
Cupello
A
A
Robello
M
M
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology; D007811:Lanthanum / Q000494:pharmacology*; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology
D018118:Chloride Channels; D011963:Receptors, GABA-A; D007811:Lanthanum