NEUROPEPTIDES IN THE CAT AMYGDALA

The distribution of seven neuropeptides was studied in the cat amygdal a using an indirect immunoperoxidase technique. No labeling was found for luteinizing hormone-releasing hormone or beta-endorphin (1-27). Sp arse alpha-melanocyte-stimulating hormone-immunoreactive fibers were f ound in the basomedial nucleus of the amygdala, whereas a low density of fibers containing alpha-neo-endorphin was observed in the anterior amygdaloid area. Neurotensin was observed in fibers of the anterior am ygdaloid area (low density) and both the lateral (low density) and the medial part (moderate density) of the central nucleus. A low density of fibers containing neurokinin A was found in the anterior amygdaloid area, the basolateral nucleus, and the medial part of the central nuc leus. A moderate density was observed in the basomedial nucleus and in the medial and cortical nuclei. Fibers containing somatostatin-28 (fr agment 1-12) were observed in all the amygdaloid nuclei, whereas immun oreactive cell bodies were found in all the nuclei except in the media l part of the central nucleus and the medial nucleus. Perikarya contai ning neurokinin A were observed in the latter nucleus. The results poi nt to a discrete distribution of peptidergic fibers in the cat amygdal a, as well as the occurrence of neurons containing neurokinin A and so matostatin-28 (fragment 1-12). The distribution of the peptides studie d in the cat is compared with the location of the same peptides in the amygdala of other species. The possible diencephalic origin of the pe ptidergic fibers is also discussed. (C) 1998 Elsevier Science Inc.