Figure 4

sst2A in human DRG and spinal cord. (a) DRG section from human. sst2A-LI is detected in very few neurons. The immunoreactivity is associated with the cell membrane (arrowheads). (b-c). sst2 mRNA is expressed in human DRG incubated with antisense probe (b; white star, sst2⁺; black asterisks, sst2^-) but not with cold probe (c; black asterisks, sst2^-). (d-g’) sst2A-LI is seen throughout the gray matter in human spinal cord with a gradient from dorsal to ventral horn (d), whereas in mouse the sst2A-LI is mainly present in lamina I and II, with some staining in lamina X and the ventral horn (e). (f-g’) Strong sst2A-LI is observed mainly in superficial layers with a modest density in deeper laminae (f). High magnifications show a dense plexus of sst2A⁺ processes (f’; box in f) and some sst2A⁺ interneurons in the dorsal horn (f”; arrowheads; box in f). sst2A⁺ terminals and motor neurons are also observed in the ventral horn (g, g’). Arrowhead indicates a motoneuron with strong membrane and relatively weak cytoplasmic sst2A-LI (g’; box in g). Scale bars indicate 20 μm (a, b, f”), 50 μm (f’, g, g’), 250 μm (e, f) and 500 μm (d).