GABAB-receptor-mediated actions of baclofen in rat isolated neocortical slice preparations: antagonism by phosphono-analogues of GABA.
Baclofen, 3-amino-propylphosphonic acid (3-APPA), and beta-phenyl-GABA (BPG), each reduced the frequency of spontaneous paroxysmal discharges in rat neocortical slices maintained in Mg2+-free medium, reversibly antagonised by phaclofen and 4-amino-butylphosphonic acid (4-ABPA). At lower concentrations, not influencing the discharges, both 3-APPA and BPG also reversibly antagonised this action of baclofen. However, des-chloro-phaclofen was inactive. Thus, phaclofen and 4-ABPA are GABAB-receptor antagonists in neocortex, whereas both 3-APPA and BPG have partial agonist/antagonist activity at cortical GABAB-receptors.
Kerr
D I
DI
Department of Pharmacology, University of Sydney, N.S.W., Australia.
Ong
J
J
Johnston
G A
GA
Prager
R H
RH
D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D011437:Propylamines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
D011437:Propylamines; D011963:Receptors, GABA-A; C052329:phaclofen; D005680:gamma-Aminobutyric Acid; D001418:Baclofen; C008842:4-amino-3-phenylbutyric acid; C011649:3-aminopropylphosphonic acid