Charlie, well done and karma for you.
I do not know where that 5 ug came from but on the other link
It is 100 nanograms or.0.1 micrograms or .0001 mg. However, the is ug per kilogram body weight.
If you weigh 200 lbs, then 200 / 2.2 = 91 kg x .1 micrograms = 9.1 micrograms, so that is close to your 5 ug or .0005 mg.
All this seems to be in error to me on LD50
....see below
Also remember these where all injected dosage. This is not like getting it on your hands unless you have a open wound and it gets into your body. And you do not want to be licking your fingers
Palytoxin is one of the most toxic non-peptide substances known, second to only Maitotoxin, which is from a dinoflagellate.
There is no reported cases of human poisoning, but animal test suggest that the toxin constricts bloodvessels in the heart.
LD50 Palytoxin
(these **seem** to be right)
.08 micrograms/kg = monkeys:
.2 microgram/kg = cats
.4 micrograms/kg = mice.
1270 microgram/kg. = mice, through skin as adsorption
~68 micrograms.068 mg = Human IV lethal dose.
The mode of action for Palytoxin is irreversible depolarization of the nerve and muscle tissue, possibly affecting sodium channels. Higher concentrations disintegrate red blood cells.
ABSTRACT:
Mechanism of palytoxin-induced [3H]norepinephrine release from a rat pheochromocytoma cell line
M Tatsumi, M Takahashi and Y Ohizumi
Palytoxin, isolated from the zoanthid Palytoha species, is one of the most potent marine toxins. Palytoxin (1 nM-1 microM) caused a release of [3H]norepinephrine from clonal rat pheochromocytoma cells in a concentration-dependent manner. This releasing action of palytoxin was markedly inhibited or abolished by Co2+ or Ca2+ -free medium, but was not modified by tetrodotoxin. The release of [3H]norepinephrine induced by a low concentration (30 nM) of palytoxin was abolished in sodium- free medium and increased as the external Na+ concentrations were increased from 3 to 100 nM, but the release induced by a high concentration (1 microM) was unaffected by varying the concentration of external Na+ from 0 to 100 mM. The release of [3H]norepinephrine induced by both concentrations of palytoxin increased with increasing Ca2+ concentrations from 0 to 3 mM. Palytoxin caused a concentration- dependent increase in 22Na and 45Ca influxes into pheochromocytoma cells at concentrations of 0.1 nM-10 nM and 1 nM-1 microM, respectively. The palytoxin-induced 45Ca influx was markedly inhibited by Co2+, whereas the palytoxin-induced 22Na influx was not affected by tetrodotoxin. These results suggest that in pheochromocytoma cells the [3H]norepinephrine release induced by lower concentrations of palytoxin is primarily brought about by increasing tetrodotoxin-insensitive Na+ permeability across the cell membrane, whereas that induced by higher concentrations is mainly caused by a direct increase in Ca2+ influx into them.
ABSTRACT:
Sea anemone Radianthus macrodactylus--a new source of palytoxin.
Mahnir VM, Kozlovskaya EP, Kalinovsky AI.
Pacific Institute of Bioorganic Chemistry, Russian Academy of Sciences, Vladivostok.
A very potent non-protein toxin was isolated from the sea anemone Radianthus macrodactylus with the use of chromatography on polytetrafluoroethylene, CM-Sephadex C-25 and by cation and anion exchange HPLC. The toxin was identified as palytoxin by u.v.-, i.r.- and 500 MHz 1H NMR spectroscopy. Its LD50 was 0.74 +/- 0.29 micrograms/kg by i.v. injection into mice. So far, palytoxin has been associated with zoanthids only. The toxin caused the loss of haemoglobin from erythrocytes but only in about 2 hr after the beginning of incubation, which is characteristic for palytoxin from zoanthids. Sea anemone palytoxin was divided into major and minor components by HPLC. The latter proved to be a product of degradation of palytoxin.
Lots more
http://content.febsjournal.org/cgi/content/full/269/16/3905