Fig. 4. A double-color immunohistochemical analysis for the rat brain slice containing the neocortex was performed to determine the localization of neuronal nitric oxide synthase (nNOS, Cy3 stain,  white arrows ), acetylcholinesterase (AChE, fluorescein isothiocyanate stain,  pink arrows ), and both (Merged,  yellow arrows ) as described in Materials and Methods. Hematoxylin and eosin (HE)-stained brain sections (at the  bottom ) were adjacent to those  upper panels. Figure shows representative results from among five different rats, with  left and  right panel from each pair being from different rats. A scale bar indicates 100 μm in length in all pictures.