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April 1973

Myotonia Induced by Monocarboxylic Aromatic Acids: A Possible Mechanism

Author Affiliations

Durham, NC
From the Division of Neurology, Duke University Medical Center, Durham, NC.

Arch Neurol. 1973;28(4):243-246. doi:10.1001/archneur.1973.00490220051007

The monocarboxylic aromatic acids 2,4-dichlorophenoxyacetic acid (2,4-D) and 3-chloro-2, 5, 6-trimethylbenzoic acid, which are myotonia-inducing agents, were found to increase the K -independent p-nitro-phenylphosphatase (basic p-NPPase) activity of microsomes isolated from normal rat skeletal muscle. The activities of K+-stimulated p-NPPase and Na+,K+-stimulated adenosine triphosphatase were unchanged. Similar findings were observed in muscle microsomes from rats made myotonic with 2, 4-D. It is proposed that increased basic p-NPPase activity is related to increased passive flux of K+ and that the latter might play a primary role in producing the myotonia.