title: A competitive displacement assay to detect saxitoxin and tetrodotoxin.
abstract: An assay is described which detects saxitoxin (STX) and tetrodotoxin (TTX) by their competitive displacement of [3H]saxitoxin from its receptor in rat brain membranes. The assay has a sensitivity of 0.15 ng STX/ml and 0.8 ng TTX/ml for buffer samples. The assay was also applied to detection of these toxins in unextracted human plasma and found to have a sensitivity of 0.5 ng STX/ml and 0.6 ng TTX/ml. The competitive displacement assay appears to be the most sensitive procedure yet for detection of STX and TTX.
mesh_terms: D029845:Amphibian Proteins; D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D008297:Male; D008832:Microchemistry; D051381:Rats; D011919:Rats, Inbred Strains; D012530:Saxitoxin / Q000032:analysis* / Q000097:blood; D015222:Sodium Channels; D013779:Tetrodotoxin / Q000032:analysis* / Q000097:blood
chemical_list: D029845:Amphibian Proteins; D002352:Carrier Proteins; D015222:Sodium Channels; C027525:saxitoxin-binding protein, Rana catesbeiana; C023790:tetrodotoxin-binding protein; D012530:Saxitoxin; D013779:Tetrodotoxin