The neurotoxin histrionicotoxin interacts with the putative ion channel of the nicotinic acetylcholine receptors in the central nervous system.
Perhydrohistrionicotoxin at micromolar concentrations blocked the nicotine-evoked transmitter release from perfused striatal (dopaminergic) and hippocampal (cholinergic) nerve terminals. Perhydrohistrionicotoxin failed to compete with [3H]nicotine for its high-affinity binding site in rat brain, suggesting that the action of this toxin on central nicotinic receptors is noncompetitive. From the dose-response curve, 50% inhibition of nicotine-evoked striatal dopamine release occurred at 5 microM perhydrohistrionicotoxin, a value similar to that obtained in frog sartorius muscle and Electrophorus electroplax. This close agreement may suggest that the ionic channel of the presynaptic nicotinic acetylcholine receptor of brain neurons has similar properties to those of the peripheral receptor.
D000109:Acetylcholine / Q000378:metabolism; D000664:Amphibian Venoms / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009498:Neurotoxins; D009538:Nicotine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
D000664:Amphibian Venoms; D007473:Ion Channels; D009498:Neurotoxins; D011978:Receptors, Nicotinic; D009538:Nicotine; D000109:Acetylcholine; C007948:histrionicotoxin; D004298:Dopamine