Glutamic acid and glutamic acid diethylester in tinnitus treatment.

Numerous recent findings indicate that in mammals glutamic acid (Glu) functions as the primary and secondary afferent cochlear transmitter, or at least as an agonist of the main transmitter. Glutamic acid diethylester (GDEE) is one of the known antagonists of Glu. A long term suppression of certain forms of tinnitus was observed dependent on the sequence, amount and perfusion rate upon i.v. application of Glu and GDEE. Consecutive controls with tinnitus detecting as well as blind studies helped to objectify the subjective sensations of the patients.