Development of Nitric Oxide Synthase Expression in the Superficial Dorsal Horn of the Rat Spinal Cord

Development of nitric oxide synthase (NOS) expression in the superficial dorsal horn of the rat spinal cord was studied using NADPH diaphorase histochemistry. At birth, no positive staining was seen in the superficial laminae of the cord. A week later, a few small positive neurons and fibers were seen in presumptive lamina II. The adult pattern of NOS expression was evident by the end of the third postnatal week.