TRANSMITTER SCREENING IN THE NERVOUS TISSUES OF THE PRAWN PALAEMONETES-VARIANS (LEACH), IN ORGAN-CULTURE

1. Nervous tissues of the decaped crusctacean Palaemonetes varians (eyes plus stalks, brain, suboesophagael ganglion and ventral cord) have been maintained in organ culture in the presence of radioactive precursors of various putative transmitters. 2. The uptake of [14C]Glu and its incorporation into GABA were measured. Radioactive Glu accumulated and was incorporated into GABA in each of the tissues studied, with the greatest accumulation being found in the ventral cord. 3. Initial rates of Glu and GABA uptake were also measured. Biphasic GABA uptake occured in the ventral cord, while both biphasic Glu and GABA uptake were found in the suboesophageal ganglion. 4. High concentrations of GABA and glutamate decarboxylase were found in the ventral cord in vivo, while the highest Glu concentration was measured in the brain in vivo. 5. Both radioactive Trp and 5-hydroxytryptophan were accumulated in each of the tissues studied, but no significant incorporation into 5 HT occurred. 6. Radioactive Tyr uptake was found in all of nervous tissues studied and trace amounts of radioactivity were found associated with tyramine (eyes plus stalks and suboesophageal ganglion), octopamine (suboesophageal ganglion and ventral cord), dopamine (eyes plus stalks) and noradrenaline (eyes plus stalks). © 1979.