Postnatal development of nitric oxide synthase type 1 expression in the lumbar spinal cord of the rat: a comparison with the induction of c-fos in response to peripheral application of mustard oil

The distribution of the neuronal isoform of the enzyme nitric oxide synthase (type 1) has been investigated in the lumbar spinal cords of neonatal rats (2–20 days old). Large multipolar neurones were present from day 2 around the central canal, in a band across the neck of the dorsal horn and at the thoracic level in the intermediolateral cell column, whereas staining was absent from laminae II. By 20 days the laminae II staining was similar to that found in the adult. NOS expression in lamina II paralleled the development of c-fos expression in this lamina in response to peripheral application of mustard oil.