[Effect of staphylococcal toxin and antistaphylococcal gamma-globulin on the electrical and contractile activity of the guinea pig myocardium].

A study was made of the action of staphylococcal toxin (ST) and its combination with antistaphylococcal gamma-globulin (ASGG) on intracellular potentials (rest potential--RP, and action potential--AP), and isometric contractions of guinea-pig auricle. ST (initial concentration 18.10(-2)Lh) diluted with normal Tyrode's solution at 1:1000, 1:100 and 1:10 (spontaneously active preparations), and Tyrode's solution with 13.5 mM KCl (evoked activity of preparations), significantly increased the duration of AP of myocardial cells. In evoked activity of preparations, RP and the amplitude of AP declined as the concentration of ST was raised. The amplitude of isometric contractions and maximal rates of their growth and fall increased under the effect of ST (1:1000) and decreased at 1:100 and 1:10. ASGG combined with ST (1:100) did not produce any protective effect on the myocardium. On the contrary, it provoked a still greater inhibition of contractility. The inhibitory action of combined ST and ASGG was seen at all ratios of ST to ASGG (use was made of ASGG shortage, equivalent amount and excess as regards ST) and reached 50% for all study characteristics of contractility. Anatoxin (inactivated toxin) combined with ASGG also produced a cardiodepressant action which was manifested in an approximately 50% decrease in the maximal rate of the growth and fall of contractions in the absence of significant changes in the contraction amplitude.