Nicholas Burdick, & Dr. Sonsoles de Lacalle
The parabrachial nucleus (PBN) is located in the pons, surrounding the superior cerebellar peduncle. Data collected from rodent models have shown that it plays an integral role in various physiological functions, including sleep and wakefulness, taste, appetite, visceral sensation, nociception, temperature regulation, itch, and chemosensation. The present work aims to identify whether the primate PBN contains the diversity of neuropeptides that have been described in rodents.
We performed a detailed literature review on this region and also mapped the distribution of calbindin (CAL), cholecystokinin (CCK), dynorphin (DYN), galanin (GAL), neurotensin (NT), somatostatin (SOM), and substance P (SP) applying immunohistochemical techniques on horizontal brainstem cross-sections obtained from four neurologically normal human subjects and five male Cebus monkeys.
Overall, cell body morphology and fiber distribution in the external lateral and external medial subnuclei were similar in both primate species, but there were clear differences in peptide distribution. Both the external lateral and external medial subnuclei contained CAL, CCK, NT, SOM, and SP immunoreactivity. DYN was observed in the external lateral PBN, and GAL was present in the central lateral and dorsal medial PBN. The external lateral subnucleus exhibited a distinct topographical distribution of GAL, CAL, CCK, DYN, and SOM, with DYN and SOM overlapping in the ventral corner of the subnucleus.
The results of our literature review and histological analysis suggest that the neuropeptide distribution in the primate Lateral PBN is similar to the one described in rodents. This allows for inferences into possible physiological parallels.