The GABAB antagonist phaclofen inhibits the late K+-dependent IPSP in cat and rat thalamic and hippocampal neurones.
Phaclofen (0.5-1 mM) reversibly inhibited the late, bicuculline resistant, K+ dependent IPSP recorded in projection cells of the cat and rat dorsal lateral geniculate nucleus and in rat hippocampal CA1 pyramidal neurones. At the same concentrations, phaclofen reversibly blocked the K+ dependent, bicuculline insensitive hyperpolarization evoked by GABA and baclofen but had no effect on the GABAA IPSP. These results represent conclusive evidence that GABAB receptors mediate the late K+ dependent IPSP in cortical and subcortical neurones.
Soltesz
I
I
Department of Pharmacology, St. George's Hospital Medical School, London, U.K.
Haby
M
M
Leresche
N
N
Crunelli
V
V
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives* / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D002415:Cats; D004558:Electric Stimulation; D005829:Geniculate Bodies / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*
D011963:Receptors, GABA-A; C052329:phaclofen; D001418:Baclofen; D011188:Potassium; D001640:Bicuculline