Artificial release of 3H-taurine after electrical stimulation of retinae

The 3H-taurine release from rat retina evoked by electrical stimulation was studied. With monophasic pulses, the release could not be reproduced with the same retina preparation unless the stimulation intensity was increased or the electrode was placed in another part of the retina. LDH was released simultaneously with 3H-taurine. When the incubation was carried out at 0 degree C immediately after the stimulation, less 3H-taurine was released as compared to 37 degrees. When the tissue was stimulated at 0 degree release occurred as well. When weak alternating current stimulation was used no release was observed. However, with strong AC current stimulation, 3H-taurine release occurred, but LDH was released as well. From these results it is concluded, that the observed 3H-taurine release was at least partially due to unspecific tissue damage. Possible reasons for artificial release are heat, pH-changes around the electrodes, chlorine generated electrolytically, and silver ions liberated from the electrode. Addition of small amounts of chlorine or silver ions to the incubation medium for 2 min instead of electrical stimulation, caused strong 3H-taurine release from retina.