Distribution of gastrin-releasing peptide/bombesin-like immunoreactive cell bodies and fibres in the brainstem of the cat.

Using an indirect immunoperoxidase technique, the location of gastrin-releasing/bombesin-like immunoreactive fibres and cell bodies in the cat brainstem was studied. A moderate or low density of immunoreactive cell bodies was observed in the nucleus of the brachium of the inferior colliculus, pericentral nucleus of the inferior colliculus, ventral nucleus of the lateral lemniscus and in the external division of the lateral reticular nucleus. The densest network of immunoreactive fibres was visualized in the interpeduncular nucleus, marginal nucleus of the brachium conjunctivum, alaminar and laminar spinal trigeminal nuclei and in the substantia nigra. The periaqueductal gray, brachium of the inferior colliculus, nucleus of the brachium of the inferior colliculus, locus coeruleus, nucleus incertus, Kölliker-Fuse nucleus, facial nucleus, medial nucleus of the solitary tract and the area postrema contained a moderate density of immunoreactive fibres, whereas the pericentral nucleus of the inferior colliculus, nucleus sagulum, cuneiform nucleus, dorsal nucleus of the raphe, superior central nucleus, central, lateral and paralemniscal tegmental fields, ventral nucleus of the lateral lemniscus, dorsal tegmental nucleus, postpyramidal nucleus of the raphe, nucleus ambiguus, accessory dorsal tegmental nucleus, dorsal motor nucleus of the vagus and the inferior olive had the lowest density of immunoreactive fibres.