Excitatory amino acids and intracellular pH in motoneurons of the isolated frog spinal cord

Double-barrelled pH-sensitive micro-electrodes were used to measure
changes of intracellular and extracellular pH in and around
motoneurons of the isolated frog spinal cord during application of
excitatory amino acids. It was found that N-methyl- -aspartate,
quisqualate and kainate produced a concentration-dependent
intracellular acidification. Extracellularly, triphasic pH changes
(acid-alkaline-acid going pH transients) were observed during the
action of these amino acids. The possible significance of such pH
changes for the physiological and pathophysiological effects of
excitatory amino acids are discussed.