Fig. 7. CTN increases the rate of neurite branching but not of neurite growth in L. stagnalis. (A) Phase-contrast images of a single PeA neuron before and 24 hours after treatment with water (control, left), 50 µM srCTN (middle) or 50 µM CTN (right). Cells were isolated and cultured in CM 24 hours before treatment. (B,C) Neurite branching but not the rate of neurite extension was selectively affected by CTN treatment. (B) Branching (as indicated by the number of new neurites) increased in CTN-treated cells as soon as 3 hours after treatment (mock control 1.50±0.39; srCTN 0.83±0.25; CTN 4.57±0.81). (C) The rate of the neurite extension did not differ between the treatments (mock control 3.77±0.67 µm/hour; srCTN 3.79±1.02 µm/hour; CTN 3.43±0.38 µm/hour). The data are presented as mean±s.e.m. and were obtained from 24 control, 21 srCTN and 44 CTN cells. Asterisk indicates significant difference (P<0.05) from control condition.