Fig. 3. Confocal photomicrographs of double immunofluorescent staining of ChAT (A and D ) and α2C(B and E ) in the dorsal horn of a normal rat. Abundant ChAT-immunoreactive neurons were observed in the superficial laminae (A ) and deeper laminae (B ). α2C-immunoreactive axons were concentrated in the superficial laminae, but no obvious cell profiles were observed there (B ). Some α2C-immunoreactive neurons were seen in the deeper laminae of the dorsal horn (E ). ChAT-immunoreactive axons were apposed by abundant α2C-immunoreactive axons in the superficial laminae (C ). ChAT immunoreactivity and α2Cimmunoreactivity were colocalized in some neurons in the deeper laminae (F , arrows). Scale bar = 100 μm. L = laminae.