[Intracellular pH of cardiac muscle after administration of potassium-magnesium-aspartate (author's transl)].

27 Sprague-Dawley rats were anesthetized with pentobarbital. Artificial ventilation was given by a Starling pump respirator via a tracheal tube. Intracellular pH of cardiac muscle was determined by means of the indirect procedure of measuring the distribution of 5,5-dimethyl-2,4-oxazolidinedione (DMO) in intra- and extracellular spaces (DMO-method). 12 rats were injected i.p. with 0.33 mval potassium-magnesium-aspartate/100 g body weight and 15 rats served as controls. Using a regression analysis, the following relationships were obtained: 1. animals injected with potassium-magnesium-aspartate pHa = --0.75 log PaCO2 + 8.535, PHi = --0.30 log PaCO2 + 7.509, pHi = 0.41 pHa + 4.036; 2. control animals pHa = --0.59 log PaCO2 + 8.308, pHi = --0.27 log PaCO2 + 7.381, pHi = 0.47 pHa + 3.503. At a pCO2 of 40 torr a pHa of 7.33 (7.36) and a pHi of 7.03 (6.95) was obtained. At an arterial pH of 7.40 the pHi was 7.07 (6.98). The results of the control group are written in brackets. -- The experiments demonstrate an increase in the intracellular buffer bases after administration of potassium-magnesium-aspartate. This effect can be recognized by a concomitant increase in the intracellular pH of 0.09 compared to the control group.