CONDUCTANCE CHANGES DURING BATH APPLICATION OF BETA-ALA-9 AND TAURINE IN GIANT INTERNEURONS OF THE ISOLATED LAMPREY SPINAL-CORD

1. (1) Input conductances of giant interneurons in the isolated spinal cord of lampreys were measured with two separate intracellular electrodes. Bath applications of 0.1-3 mM β-alanine and taurine produced large, reversible conductance increases which were Cl--dependent. 2. (2) Strychnine at 1-2.5 μM might be a competitive antagonist of both amino acids, but had a stronger effect on taurine. Bicuculline and picrotoxin were weak antagonists of β-alanine and taurine in some cells. 3. (3) A few giant interneurons desensitized after repeated application of the amino acids, but most became more sensitive. Responces to the amino acids also increased at low temperatures and in Na-free fluid, suggesting effect of uptake mechanisms. © 1979.