title: Adenosine inhibition of gamma-aminobutyric acid release from slices of rat cerebral cortex.
abstract: 1 The effect of purine compounds on the potassium-evoked release of 14C-labelled gamma-aminobutyric acid (GABA) has been studied in 400 micrometers slices of rat cerebral cortex in vitro. 2 Adenosine and adenosine 5' monophosphate (AMP) inhibited the release of GABA at 10(-5) to 10(-3) M. Adenosine triphosphate (ATP) produced a significant inhibition of release only at 10(-3) M. 3 Theophylline 10(-4) or 10(-3) M reduced the inhibitory effect of adenosine, but did not change basal release of GABA. 4 Dipyridamole 10(-5) M itself reduced evoked GABA release, but did not prevent the inhibitory effect of adenosine, implying that adenosine was acting at an extracellularly directed receptor. 5 Calcium removal or antagonism by verapamil reduced the evoked release of GABA, but adenosine did not produce any further reduction of the calcium-independent release. This may indicate that the inhibitory effect of adenosine on GABA release results from interference with calcium influx or availability within the terminals.
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D003864:Depression, Chemical; D004176:Dipyridamole / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013806:Theophylline / Q000494:pharmacology; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D000249:Adenosine Monophosphate; D005680:gamma-Aminobutyric Acid; D004176:Dipyridamole; D000255:Adenosine Triphosphate; D013806:Theophylline; D000241:Adenosine; D011188:Potassium; D002118:Calcium