Pharmacology
Surugatoxin is a specific, reversible, competitive antagonist of ganglionic nicotinic acetylcholine receptors (nACHRs). Although a number of articles were published in the two decades following the discovery of SGTX in the mid-1960s, relatively little is known about the pharmacological properties of this toxin. Ascher and colleagues posit that ganglionic blockade by SGTX results from binding to the closed state of the channel-receptor complex, possibly to the receptor itself. It is 50-100 times more potent than hexamethonium, another ganglionic antagonist of nAChRs. Brown and colleagues found that the SGTX dissociation constants measured at equilibrium block in rats were 58nM and 76nM, as measured from the shift in depolarization produced by 0.2μM and 2 μM SGTX, respectively. Surugatoxin is listed on two U.S. patents, both for potential clinical treatments. U.S. Patent 7,468,188 proposes the use of locally-administered neurotoxins in the treatment of muscle injury and U.S. Patent 7,214,700 proposes the use of (2-Oxindol-3-ylidenyl) acetic acid derivatives as protein kinase inhibitors. Surugatoxin has not been demonstrated to be effective in either of these treatment proposals, but rather, is listed as a potentially relevant substance in these treatment plans.
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