Fig. 3.

Naive and pre-axotomized neurons extend different types of neurites in acute cultures. A, Naive adult DRG neurons after 16 hr under standard plating conditions extend neurites that are highly branched and extend over a limited radius, terminating in large, palmate growth cones with numerous filopodia.B, Neurites in 16 hr cultures from previously axotomized rats (1, 2, 4,5) or in 40 hr cultures from naive rats (3) branch much less frequently, often exceed 1–2 mm in length, and tend to fasciculate with other processes. Growth cones are typically tapered with few filopodia (5). Immunoperoxidase labeling with antibodies to major neuronal proteins stained all neurons to varying degrees and were often used to facilitate counting: GAP-43 (A: 1,2, 5, 6; B:1–3), NF-H (A:4; B: 4), or MAP-2 (A: 3). Scale bar, 75 μm.