PKCβ labeling of the NMJ. Over a background of more diffuse staining, two stronger bands are seen (double arrows). One band codistributes with nAChR. The other band, found in the presynaptic region, parallels the nAChR band and may be labeling the presynaptic membrane. In addition to these bands, there are strong pockets of immunoreactivity in other areas of the presynapse (arrowheads). There appears to be no association of PKCβ with the mitochondrial label. PKCβ labeling in the muscle fibers is faint, scale bar = 10 μm.