Effect of veratrine on water, sodium and potassium transport in the frog sartorius muscle
Cseri, J.; Varga, E.
Acta Physiologica Academiae Scientiarum Hungaricae 51(1-2): 1-12
1978
ISSN/ISBN: 0001-6756 PMID: 314227 Document Number: 136457
The effects of veratrine on water, Na and K distribution in the frog sartorius muscle were studied. In response to veratrine, muscle intracellular water content increased by 13% in 15 min and by 33.6% in 60 min. Intracellular Na content was augmented by 163% in 1 h. Treatment for an additional period of 60 min, the Na content increased by 266% of the control. Compared to Na content, changes in intracellular Na concentration were less pronounced, but still considerable because of the simultaneous increase of water content [Na]i [intracellular Na concentration] increased by 86% in 1 h and by 153% for 2 h. On veratrine treatment, muscle total K content decreased by 3-6% in 15 min and no further changes occurred over a period of 2 h. The 33% water uptake in turn caused a 30% reduction in intracellular K concentration. This might be a prominent factor in the development of depolarization. Net Na uptake was more marked in muscles with relatively lower intracellular Na concentration prior to veratrine treatment. Curare treatment [0.05 mM] diminished the elevation of muscle intracellular Na content caused by veratrine. Veratrine [0.1 mM] evoked a significant increase in muscle intracellular Na content even when extracellular Na concentration was reduced to 20 mM. Active processes may be partly involved in the enhancement of Na uptake by veratrine. In Ringer's solution made hypertonic by sucrose, 0.1 mM veratrine failed to induce the changes in water, Na and K content occurring in isotonic Ringer's solution, and no depolarization developed. In Ringer's solution made hypertonic by NaCl, intracellular water and Na content and Na concentration increased and depolarization ensued.