[Effect of low doses of sodium fluoride on the resistance of m. sartorius of frog to the injurious action of this substance].

A study was made of the effect of the preliminary maintenance of m. sartorius in 0.025 M NaF on their resistance to the injurious dose (0.12 M NaF). In the winter frogs, the muscle resistance to 0.12 M NaF increased statistically significant after 10 and 15 minutes maintenance in 0.25 M NaF by 27.8 and 34.6%, respectively. In spring frogs, the resistance increases as soon as after a 5 minutes preincubation by 22.5% (P less than 0.05). A 15 minutes incubation produced a similar effect as that observed in winter (32.8% P less than 0.05) A 15 minutes maintenance of muscles in a weak solution of NaF while increasing their resistance to the inhibitor was found to decrease their resistance to an injurious ethanol solution (3.48 M), and to 36 degrees, by 58 and 53%, respectively.