Uptake and stimulus-evoked release of [3H]-gamma-aminobutyric acid by myenteric nerves of guinea-pig intestine.
1--Following preloading with [3H]-gamma-aminobutyric acid ([3H]-GABA), in the presence of beta-alanine to inhibit glial uptake of the label, electrical stimulation caused a frequency-dependent release of tritium as [3H]-GABA from isolated longitudinal-muscle myenteric-plexus preparations of the guinea-pig ileum and colon. 2--The electrically evoked efflux of [3H]-GABA was Ca2+-dependent, virtually abolished by preventing neuronal conduction with tetrodotoxin, and markedly reduced by preloading with [3H]-GABA in the presence of nipecotic acid which is an inhibitor of high affinity GABA-uptake. Veratridine and KCl were less effective than electrical stimulation in evoking [3H]-GABA release. 3--It is concluded that the electrically stimulated efflux of [3H]-GABA originated from GABAergic neurones of the myenteric plexus which had taken up the label. 4--These results provide further evidence to support the suggestion that GABA is a transmitter in the mammalian enteric nervous system.
D000818:Animals; D002118:Calcium / Q000502:physiology; D003106:Colon / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000378:metabolism; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D009197:Myenteric Plexus / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid; D002118:Calcium