R-(-)-beta-phenyl-GABA is a full agonist at GABAB receptors in brain slices but a partial agonist in the ileum.
R-(-)-beta-phenyl-GABA has been compared at GABAB receptors using cortical and ileal preparations. R-(-)-beta-phenyl-GABA (EC50 = 25 microM) was a less potent full agonist than R,S-(+/-)-baclofen (EC50 = 2.5 microM), in depressing CA1 population spikes of rat hippocampal slices, and 5 times less potent in attenuating the spontaneous discharges of rat neocortex. However, R-(-)-beta-phenyl-GABA (100-400 microM) was only a weak partial agonist in the ileum. All these actions were sensitive to CGP 35348 (3-aminopropyl-(P-diethoxymethyl)-phosphinic acid) and therefore mediated by GABAB receptors.
Department of Anaesthesia and Intensive Care, University of Adelaide, South Australia.
J
J
Ong
D I
DI
Kerr
D J
DJ
Doolette
R K
RK
Duke
K N
KN
Mewett
R D
RD
Allen
G A
GA
Johnston
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects*; D013237:Stereoisomerism; D014149:Tranquilizing Agents / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
D009943:Organophosphorus Compounds; D011963:Receptors, GABA-A; D014149:Tranquilizing Agents; D005680:gamma-Aminobutyric Acid; C066430:CGP 35348; C008842:4-amino-3-phenylbutyric acid