Actions of nortetrodotoxin on frog muscle and squid axon.
Nortetrodotoxin, prepared by oxidation of the C6 end of tetrodotoxin, probably exists in solution as an equilibrium mixture of a hemilactal and a lactone form of a hydrated ketone of C6. On both frog muscle fibers under constant-current conditions and squid giant axon under voltage-clamped conditions, nortetrodotoxin selectively blocks the sodium channel. On frog muscle fibers, the solution of nortetrodotoxin used, which was several months old, was 1/13 as active as tetrodotoxin. On the squid giant axon, a freshly prepared solution of nortetrodotoxin was about 1/4 as active. These observations indicate that nortetrodotoxin possesses a substantial degree of biological activity. The suitability of nortetrodotoxin as an intermediate for synthesizing derivatives of tetrodotoxin is discussed.
D000818:Animals; D001369:Axons / Q000187:drug effects*; D049832:Decapodiformes; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D009132:Muscles / Q000187:drug effects*; D011894:Rana pipiens; D012964:Sodium / Q000378:metabolism; D013329:Structure-Activity Relationship; D013779:Tetrodotoxin / Q000031:analogs & derivatives* / Q000494:pharmacology
D007473:Ion Channels; D013779:Tetrodotoxin; C036588:11-nortetrodotoxin; D012964:Sodium