Acute toxicity of gymnodimine to mice.
The acute toxicity of the phycotoxin gymnodimine to female Swiss mice by intraperitoneal injection and by oral administration has been determined. Gymnodimine was highly toxic by injection, the LD50 being only 96 microg/kg. Animals either died within 10 min of injection or made a full recovery with no perceptible long-term effects. Gymnodimine was also toxic after oral administration by gavage (LD50 755 microg/kg), but was much less toxic when administered with food. No signs of toxicity were seen in mice voluntarily ingesting food containing gymnodimine at a level sufficient to give a dose of approximately 7500 microg/kg. Pre-treatment with physostigmine or neostigmine protected against injected gymnodimine, suggesting that the latter exerts its toxic effects via blockade of nicotinic receptors at the neuromuscular junction. The low toxicity of gymnodimine when ingested with food suggests that this compound is of low risk to humans, a conclusion that is consonant with anecdotal evidence for the absence of harmful effects in individuals consuming shellfish contaminated with gymnodimine.
Munday
Rex
R
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand. rex.munday@agresearch.co.nz
Towers
Neale R
NR
Mackenzie
Lincoln
L
Beuzenberg
Veronica
V
Holland
Patrick T
PT
Miles
Christopher O
CO
D000284:Administration, Oral; D000818:Animals; D016001:Confidence Intervals; D004141:Dinoflagellida; D004386:Duodenum / Q000378:metabolism; D005260:Female; D006575:Heterocyclic Compounds, 3-Ring / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D006844:Hydrocarbons, Cyclic / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D006863:Hydrogen-Ion Concentration; D007097:Imines / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D007274:Injections, Intraperitoneal; D007408:Intestinal Absorption; D007928:Lethal Dose 50; D008387:Marine Toxins / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D051379:Mice; D023382:Toxicity Tests, Acute
D006575:Heterocyclic Compounds, 3-Ring; D006844:Hydrocarbons, Cyclic; D007097:Imines; D008387:Marine Toxins; C407350:gymnodimine