Figure 1

Laminin stimulation elicits lamellopodia and process formation in adult sensory neurons. DRG neurons plated on polylysine were stimulated with laminin in solution for 5 min, 15 min, 30 min, 1 hr, 6 hrs, 24 hrs. After fixation, neurons were stained with rhodamine-phalloidin to detect actin and images obtained using confocal microscopy. Panels A-F provide representative examples of the various stages of lamellopodia formation and eventual process protrusion, and show various distinctive stages in neuronal membrane expansion and neurite growth. At the earliest stages, lamellopodia are formed (A- 5 min, B- 15 min, C- 30 min) with evidence of focal contacts (arrows) at the leading edge of the lamellopodia (B, C). In D (1 hr) and E (6 hrs) filopodia begin to protrude from the lamellopodium around the circumference of the neuron. Eventually, these processes appear to coalesce into one or more neurites that continue to extend (F- 24 hrs, arrow). Scale bar – 20 μm.