STUDIES ON THE PHYSIOLOGICAL EFFECTS OF NON-POLAR-POLAR ORGANIC ELECTROLYTES I. THE INfLUeNCE UPON T~ RESTING POTENTIAL 0~' FRoo MUSCLE

A variety of single observations has suggested a systematic and detailed study of the physiological properties of the large group of non-polar-polar organic electrolytes, which as detergents, as wetting and dispersing agents, play an ever increasing r61e not only in technical processes, but also in microbiological research as bacteriostatic and bactericidal agents, the nature of which draws to this field the attention of physiological chemists and physical chemists. My own interest was primarily aroused by observing the secretory activity of the kidney with respect to acidic and particularly sulfonic acid azo dyestuffs (1, 2). These have been found to reveal a striking selective behavior toward the proximal tubules, which is due partially to lipoid solubility, partially to the molecular volume equipping the dye with crystalloidal, semicolloidal, or colloidal properties. However, in addition, evidence was brought forth that for penetration into the kidney epithelia and, moreover, for subsequent accumulation of the dye in the secretion a conditioning factor is a special molecular configuration of the dye, namely the location in the molecule of the sulfonate groups, rendering its structure either non-polar-polar or polar-polar. In the first case, the dye molecules were assumed to stick by surface activity of their non-polar organophilic halves to the cell surface, whereas the polar hydrophilic halves would be anchored in the aqueous surroundings, resulting in a molecular orientation like that of the soap molecules in a Langmuir film. In the second case of polar-polar structure the effective attachment to the kidney cells would be absent and secretion would fail to appear. However, the effect of a nonpolar-polar configuration should be considered specifically different from that of lipoid solubility or of molecular size, as in both of these latter cases the membrane may remain unaltered, whereas, if a non-polar-polar compound is present, the cell surface can be subjected to a pull of antagonistic forces the strength of which would depend upon the qualities of the two halves and therefore could produce a (reversible) distortion or even an (irreversible) disintegration of the delicate architecture of the cell surface or its components (3-5). In this way, the effect of non-polar-polar substances can be thought of as causing 389