An upper limit to the number of sodium channels in nerve membrane?
1. A small volume of artificial sea water containing 300 nM tetrodotoxin (TTX) was applied successively to seven lobster nerve trunks and the cumulative uptake of toxin investigated by bio-assay.2. Light and electron microscopy indicated that the nerve trunks had a total axonal area of 0.7 x 10(4) cm(2)/g.3. Sodium analysis gave a sodium space for the nerve trunks of 30%.4. The amount of toxin taken up by the cells in 1 g of nerve is less than 1.6 x 10(-11) moles.5. It is argued that there are probably fewer than 13 sodium channels/mu(2) axon in lobster nerve.
D000200:Action Potentials; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D003445:Crustacea; D004594:Electrophysiology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D012964:Sodium / Q000032:analysis*; D013779:Tetrodotoxin / Q000494:pharmacology; D014118:Toxins, Biological / Q000494:pharmacology*
D014118:Toxins, Biological; D013779:Tetrodotoxin; D012964:Sodium