Fluorescence histochemistry of monoamine‐containing cell bodies in the brain stem of the squirrel monkey (<i>Saimiri sciureus</i>). III. Serotonin‐containing groups

Abstract

Abstract The distribution and cytological characteristics of the serotonin‐containing cell bodies in the brain stem of the squirrel monkey ( Saimiri sciureus ) are described using the fluorescence histochemical technique of Falck and Hillarp for the demonstration of monoamines. Eight groups of serotonin‐containing neurons were found, located predominantly in the midline raphe region of the brain stem within defined nuclei, such as the nucleus raphe obscurus, nucleus raphe pallidus, nucleus raphe magnus, nucleus raphe pontis, nucleus raphe dorsalis and nucleus centralis superior. Portions of some of the groups also extend laterally in the brain stem, particularly at the levels of the upper pons and midbrain. The appearance and distribution of the serotonin‐containing groups of cell bodies in the squirrel monkey were found to be somewhat similar to that described for the rat, but differed in at least one major respect from that reported for the cat.