Rapid Peripheral Disintegration of Planaria in the Presence of Barium

Bioelectric signalling has been implicated in planaria regeneration and anatomical homeostasis. Previous reports demonstrated that barium chloride (1 mM), a potassium channel blocker, produced slow disintegration of the head (in 72 hours) in a clonal strain of Dugesia japonica. To investigate whether the effects of barium were similar in all planaria species, I tested its effects in wild Girardia sp. collected from a stream. The results were significantly different from those seen in Dugesia japonica: At 1 mM, these worms underwent complete peripheral disintegration within thirty minutes.