Antagonistic effect of delta-aminovaleric acid on bicuculline-insensitive gamma-aminobutyric acid B (GABA B) sites in the rat's brain.
The effect of delta-aminovaleric acid (delta-AV) on bicuculline-insensitive gamma-aminobutyric acid B (GABA B) sites in the central nervous system (CNS) was investigated by binding studies and experiments on slices in vitro. delta-AV inhibited [3H]GABA (10 nM) binding to GABA B sites in a rat brain membrane preparation with an IC50 value of 10(-4) M. It also inhibited [3H]baclofen (20 nM) binding with an IC50 value of 10(-4) M. In preparations of hippocampal slices, (-)-baclofen (5 microM) reduced the population spikes evoked by stimulating the Schaffer collaterals in CA1 pyramidal cells in the presence of 100 microM bicuculline. delta-AV (1 mM) antagonized this inhibitory action of baclofen. Since baclofen is an agonist of GABAB sites, our results indicate that delta-AV has an antagonistic effect on GABAB sites in the CNS.
Nakahiro
M
M
Saito
K
K
Yamada
I
I
Yoshida
H
H
D000596:Amino Acids / Q000494:pharmacology*; D021542:Amino Acids, Neutral; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D001667:Binding, Competitive; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D000596:Amino Acids; D021542:Amino Acids, Neutral; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; C013809:5-aminovaleric acid; D001418:Baclofen; D001640:Bicuculline