[Effect of maintaining the grassfrog sartorius muscle in a 0.002 M solution of alpha-dinitrophenol on its sensitivity to a 0.004 M solution of that substance].

A study was made of the effect of a preliminary maintenance of m. sartorius of Rana temporaria in 0.002 M alpha-dinitrophenol (alpha-DNP) on the resistance of muscles to 0.004 M concentration of this substance. The incubation of muscles in 0.002 M alpha-DNP for 10--20 min results in a statistically significant increase in their resistance to 0.004 alpha-DNP (24.8--30.7%). The highest increase in resistance was observed after a 20 minutes' maintenance of muscles. Therefore on studying the effect of 0.002 M alpha-DNP on the resistance of muscles to the injurious concentrations of chloral hydrate (0.08 M), ethanol (3.48 M), or 36 degrees, the muscles were maintained in the inhibitor for 20 minutes. In the case of a 20 minutes' maintenance of muscles in 0.002 M alpha-DNP, their resistance to chloral hydrate increased by 24.8%, whereas that to ethanol or heating decreased by 23.3 and 37.8--64.6%, respectively.