Figure 2.

Activin receptors are expressed in intact as well as cultured DRG neurons. A, Immunohistochemical detection of ActRI, ActRIB, ActRII, and ActRIIB in sections of adult DRG as indicated by brown DAB reaction product. It is apparent that receptors are expressed in most neurons and nerve fibers within the ganglion. No reactivity was observed in sections in which primary antibody was omitted. B, C, Phase and pseudocolor fluorescence images of cultured DRG neurons. Primary antibody conditions are labeled on each fluorescence panel. ActRIB, ActRII, and ActRIIB immunoreactivity was detected by immunocytochemistry in all identified neurons, including TRPV1-expressing small and medium-size neurons.