inactivation curve to the left (16.2 mV) without any effects
on the inactivation curve.
3.4. Estimated amount of toxin contents in the muscle or liver
of various puffers
The toxin extracts of puffers selectively suppressed INa of
rat hippocampal CA1 neuron as described above. Therefore,
it was possible to estimate the amount of toxin in the
muscle or liver prepared from various puffers as an amount
of equipotent TTX by comparing IC50 of the toxin extracts
shown in Figs. 4 and 6. Fig. 8 summarizes the mean value of
toxin content expressed as the amount of mg TTX/g in
muscle or liver from the five puffer species. The toxin level
in liver was much higher than in muscle, and the amount of
toxin in liver of T. rubripes and T. vermicularis was more than