ON MECHANISM OF NEUROMUSCULAR BLOCKING ACTION OF COBALT ION

The effecls of coball chloride on the ‘in situ’ neuromuscular transmission of the dog were studied. Administration of the cation by close-arterial injection produced a persistent neuromuscular blockade whereas the response of the tibialis-anticus to indirect stimulation was not affected by the cobalt chloride intravenously injected. The contraction of the tibialis-anticus to direct stimulation was not prevented by cobalt chloride. Calcium chloride instantly antagonized the neuromuscular blockade produced by cobalt ion. Neostigmine was able to overcome the blockade induced by cobalt chloride but always partially. A magnesium-like mechanism is suggested for the neuromuscular blockade produced by cobalt. © 1969 S. Karger AG, Basel.