Fig. 6. Reversibility of the effect of TTX on the galvanotactic behaviour of MAT-LyLu cells in an electric field of 3 V cm^-1. The experiments started with the cells just treated with the toxin (5 µM) whereby the average cosine of directional segmental angle ß (calculated from 50 trajectories) was near zero (i.e. there was little directionality in the movement). The toxin was washed after 3 hours of recording (at the moment indicated by the arrow), whereupon the directionality of response was restored. Other details as in Fig. 5.