Rate of antagonism of tubocurarine by potassium ions.

The rate at which potassium ions antagonized the neuromuscular block produced by tubocurarine has been examined in isolated rat diaphragm muscle preparations. The half-time was dependent on the thickness of the muscle. In thick muscles (550 to 650 mu) the rate of action could be largely accounted for by the time which the potassium took to diffuse through the interstitial fluid to produce an increase in concentration in the immediate environment of the muscle fibre.