title: Tetrodotoxin-sensitive ion channels characterized in glial and neuronal cells from rat brain.
abstract: Ion channels were studied in primary neuronal and in primary glial cultures from rat brain by measuring the uptake of guanidinium, an ion that can permeate the Na+ channel. Neuronal cells exhibit a veratridine-stimulated (EC50 30 microM) guanidinium uptake, which is blocked by tetrodotoxin (IC50 30nM). This demonstrates the presence of a voltage-dependent Na+ channel. In glial cells veratridine + scorpion toxin, but not veratridine or scorpion toxin alone can stimulate a tetrodotoxin-sensitive ion uptake, thus indicating a 'silent' Na+ channel in the glial cells. Phentolamine, propranolol and various local anesthetic drugs (e.g. tetracaine, dibucaine) blocked the two different kinds of Na+ channels in the two cell populations investigated.
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002478:Cells, Cultured; D007473:Ion Channels / Q000187:drug effects*; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D007473:Ion Channels; D013779:Tetrodotoxin; D014701:Veratridine; D012964:Sodium