[Histopathological and electron microscopic changes in mice treated with puffer fish toxin]

The histopathological examination of a male ddY mouse given an intraperitoneal injection of the crude extract containing 169 micrograms/ml of tetrodotoxin (TTX) prepared from the ovary of Takifugu porphyreus was carried out. Two crude extract solutions (0.42 and 0.21 microgram/ml) were prepared; one kills an animal in 10 min (group 1), and other kills it in 40 min (group 2) after the injection. As a result, a remarkable inflation of the gall bladder was observed macroscopically in both groups. By light microscopic observed, both groups showed the congestion in the brain, heart, liver, gall bladder, lung and kidneys, while nerve cells were characterized by the vacuolation and disappearance of Nissl's body only in group 2, probably because of the mitochondrial degeneration. Electron microscopically, a part of cristae of mitochondria and ribosome of endoplasmic reticulum disappeared or vacuolated in the nerve cells of group 2. This was also observed in a part of pre and postsynaptic mitochondria of synapse. However, little significant changes were observed in group 1 and in other tissues of group 2. These results show that a cytopathological change of mice by TTX is mainly detected in nerve tissues when a small amount of TTX is administered to the animals.