TTX displacement of [H3]-nitrendipine binding in developing spinal cord neurons

3H] Nitrendipine binding was partially blocked by the presence of tetrodotoxin in developing spinal cord neurons. In young cultures, 1 micron tetrodotoxin displaced 29% and 26% of 3H] nitrendipine binding from the high and low affinity binding sites, respectively. In one month old cultures, tetrodotoxin had no effect on 3H] nitrendipine binding. The interaction between tetrodotoxin and nitrendipine in young cultures suggests ligand binding site similarities during development.