The effect of gamma-aminobutyric acid on the potassium movements of rat cortical synaptosomes.
K+ fluxes of rat cortical synaptosomes were monitored by a K+ sensitive ion-selective membrane electrode. The uptake phases of K+curves from control and experimental measurements were compared and statistically evaluated. GABA significantly reduced K+ uptake but it was able to reverse the decrease of K+ uptake caused by protoveratrine. In the absence of Ca2+ the K+ uptake was diminished; GABA had no effect on this inhibition. The effect of GABA on K+ take was partially reduced by bicuculline and abolished by diamino-butyric acid. The K+ content of synaptosomes decreased, while the NA+ content increased in the presence of GABA. The results are discussed in association with presynaptic depolarisation and with modulatory effects of GABA on the release of other transmitters.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D011526:Protoveratrines / Q000494:pharmacology; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D007473:Ion Channels; D011526:Protoveratrines; D005680:gamma-Aminobutyric Acid; D011188:Potassium; D002118:Calcium