Effects of protamine and acridine orange on the muscular activity of the guinea-pig's uterus

Studying the exciting effects of protamine and acridine orange on the guinea-pig's uterus it was demonstrated that both substances accumulated within the nucleus of the muscle cell. Other basic substances, such as naphthylamines and benzidine, which, though penetrating into the cells, did not accumulate within the nucleus, did not activate the smooth muscle. The cell respiration was not altered by the basic substances. The results are discussed with regard to the role of the cell nucleus in the autorhythmical activity of the smooth muscle.