Title: Comparison of the Force Exerted by Hippocampal and Drg Growth Cones
Abstract: Using optical tweezers, we have compared the force exerted by lamellipodia and filopodia from developing growth cones of isolated hippocampal neurons and Dorsal Root Ganglia (DRG) neurons obtained from P1-P2 and P10-P12 rats. Lamellipodia of DRG neurons were usually larger than those from hippocampal neurons and the proportion of filopodia with microtubules in their interior was higher in hippocampal than in DRG neurons. Filopodia from hippocampal growth cones exerted a large force often in the order of 5 pN, while the force exerted by filopodia of DRG growth cones was in the order of 1-2 pN and never exceeded 5 pN. Lamellipodia of both hippocampal and DRG growth cones exerted lateral forces up to 20 pN, but lamellipodia from DRG neurons could exert a vertical force larger than lamellipodia from hippocampal neurons. Therefore, the lateral force exerted by lamellipodia from peripheral nervous system (PNS) and central nervous system (CNS) neurons at different developmental stages is broadly similar but hippocampal filopodia could exerted a force larger than that of DRG filopodia.