Tracer Studies of the Uptake of Organic Compounds by Planarians

Abstract

For this symposium it is superfluous to review either the numerous theories of memory or the interest that has existed, and for many still exists, in planarians as a useful tool in studies of chemical processes which occur in learning. Because of this interest in planarians, a few years ago we attempted to train planarians reliably and reproducibly. At the same time we studied the uptake of a number of organic compounds by planarians. Our objective was not to investigate the intermediary metabolism of these compounds in detail, but rather to determine in a general way (1) the relative efficiency with which different classes of organic compounds were utilized, (2) the variation within a class of the degree of utilization, and (3) some variables which influence uptake. The parameters affecting uptake which we studied included the external concentration of the organic compounds and the time of contact. In addition, the rate of loss of the label when the planarian was removed from the tracer solution and the distribution of the utilized chemical between “soluble” and “insoluble” compounds were determined. The retention and distribution of the label when transferred by cannibalism were also investigated. Radioautographic studies were carried out to confirm the uptake of the tracer compounds and to investigate their distribution among cells of the planarian.

This research was supported by the U.S. Atomic Energy Commission.