Palytoxin pharmacological action

As mentioned above, palytoxin produces multiple pharmacological actions at the cellular, tissue, and organism level. Alterations in the Na" and gradients by the toxin will initiate a complex chain of cellular events it could alter the active transport of various ions as well as the transport processes across intracellular membranes. One important parameter that can be altered by palytoxin is the cytosolic free calcium concentration, which will produce alterations in numerous cellular processes. 

Palytoxin is probably one of the most potent toxins known to humans. Intravenous LD q values in the sue species that have been studied are consistently less than 0.5 ig/kg. In addition, palytoxin possesses a speed of action and other pharmacologic properties that are markedly different from those exhibited by other toxic materials. For example, when injected iv or sc, palytoxin is extremely toxic yet when given po or ir, it is relatively non-toxic. It is also very interesting that the doses of palytoxin required to kill are somewhat different in anesthetized vs. unanesthetized animals. 

The study of the compounds that inhibit the action of palytoxin has focused primarily on the inhibition of the pharmacological target of the toxin, that is, the Na, K -ATPase however, other inhibitors of several transport systems can also affect the action of palytoxin, since several transport systems are activated after the palytoxin-induced increase in the cationic permeability of the cell. 

Frelin, C. and Van Renterghem, C., Palytoxin. Recent electrophysiological and pharmacological evidence for several mechanisms of action, Gen. Pharmacol. 26, 33, 1995. 

Tan, C.-H. andLau, C.-O., Chemistry and Detection, in SeafoodandFreshwater toxins Pharmacology, Physiology and Detection, Botana, L.M. (Ed.), Marcel Dekker Inc, New York, 2000, p. 533. Habermann, E. et al., Delayed haemolytic action of palytoxin. General characteristics, Biochimica et Biophysica Acta 649, 481, 1981. 

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