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Hey everyone.

The Kaplan Physiology book has a table on pg.36 that lists the causes of INCREASED Neuronal Excitability/Conduction.

In it are listed the two toxins: ciguatoxin and batrachotoxin. Their mode of action is explained in the Bridge to Pharmacology as blocking the inactivation of fast Na+ channels. This should mean that these toxins, by prolonging the time for which Na+ channels remain open, prolong the absolute refractory period of action potentials. This would mean neuronal excitability is DECREASED by these toxins, correct?

A quick search on Google agrees that neuronal firing rate is decreased by ciguatoxin and the symptoms of Ciguatera are more suggesting of DECREASED neuronal excitability - ataxia, numbness (paresthesias are for any alteration in neuronal excitability).

I feel like I'm missing something obvious here. Help? Happy-2

Thank you.
 
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