Effects of HCRPs on neurite growth. A,B: Neurite growth profile of cultured Helix neurons in the presence of the mouse F3/contactin antiserum (24III) or in the presence of the corresponding preimmune serum (control) at 48 hr. C: Graphic representation of neurite growth of Helix neurons in the presence of mouse F3/contactin antiserum (24III) or in the presence of the corresponding preimmune serum (control). Neurite elongation was followed over 48 hr and is shown at 24 and 48 hr. Each point represents the percentage mean value (±SEM) of radius length of a circumferential line interconnecting the tips of the three longest neurites, normalized to the control mean value measured at 24 hr (567.2 μm). Two-way analysis of variance (repeated measures) indicates a significant effect of treatments (F1,9 = 276.93, P < 0.001) and time (F1,9 = 6.205, P < 0.05) and a significant interaction between time and treatments (F1,9 = 43.69, P < 0.001). Scale bars = 100 μm.