FIGURE 2.

Short-term transplants: presynaptic inputs from the host to transplant cell bodies. (a & d) Immunoperoxidase reaction product identifies GFP-immunoreactive transplant cell bodies (NCB_T) in the dorsal horn (DH). Boxed areas in (a) (Boxes b, c) and in (d) (Box e) illustrate unlabeled (host) axon terminals presynaptic (arrowheads) to GFP-labeled transplant cell bodies. In (a), the transplant cell body receives both an asymmetric and a symmetric synapse. The density postsynaptic to the unlabeled terminal in (b) is thick (i.e., an asymmetric synapse) whereas the density postsynaptic to the unlabeled terminal in (c) is thin (i.e., a symmetric synapse). In (d), the cell body of a GFP-negative (host) neuron (NCB_H) and a glial cell (G) abut the GFP-positive transplanted cell body. (e) The unlabeled axon terminal in (e) directly contacts (double arrowhead) the GFP-positive cell body in (d), without an intervening glia process and also forms a symmetric synapse (arrowheads) with an unlabeled host cell body. Nuc, neuronal nucleus. Scale bars: 2 μm in (a, d); 500 nm in (b, c, e)