TPP+ accumulation in rat brain synaptosomes as a probe for Na+ channels.
Tetraphenylphosphonium (TPP+) accumulation in rat brain synaptosomes was measured in the presence of various stimuli. TPP+ accumulation was sensitive to an increase of extracellular K+ or to the presence of Na+ channel neurotoxins. Examination of the effects of drugs with different physico-chemical properties on TPP+ accumulation showed that there was no effect under low and high K+ conditions; pimozide, flunarizine and buterizine were active in the presence of veratridine or scorpion venom. These results were compared to data obtained for the specific binding of [3H]BTX-B, a selective marker for the Na+ channel. It can be concluded that certain drugs, although active on [3H]BTX-B binding, are not necessarily identified when TPP+ is used as probe.
D000818:Animals; D001496:Batrachotoxins / Q000494:pharmacology; D001923:Brain Chemistry / Q000187:drug effects*; D005260:Female; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D011188:Potassium / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
D001496:Batrachotoxins; D007473:Ion Channels; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D012964:Sodium; D011188:Potassium; C013289:tetraphenylphosphonium