STUDIES ON THE UPTAKE AND RELEASE OF RADIOACTIVE TAURINE BY THE FROG RETINA

Abstract

Abstract— Taurine is taken up into the frog retina by active, sodium dependent, temperature sensitive systems that show both high and low affinity for the amino acid ( K m about 50 μ m and 2 m m respectively). Autoradiographs from retinae incubated in radioactively labelled taurine showed heavy grain density over cell bodies in the position of amacrine interneurones and over specific strata in the inner synaptic layer of the tissue. Photoreceptor cells were also labelled. Taurine, once accumulated by the frog retina, is not lost during the incubation and is only slowly metabolised. Electrical stimulation caused taurine release above the level of spontaneous efflux but light or depolarisation of the tissue with 40m m ‐potassium chloride did not.