chapter  Chapter 5
24 Pages

Miscellaneous Neuropeptides

WithPaul V. Malven

This chapter summarizes knowledge about various neuropeptides, with the greatest emphasis on the opioid neuropeptides. Pharmacological antagonism of endogenous opioids increased the level of substance P messenger RNA in the striatum, suggesting an interaction between substance P and opioid neuropeptides. Endogenous opioid peptides (EOP) neurons often contain other non-opioid neuropeptides or receptors that are important in neuroendocrine integration. EOPs were contributing to the feeding behavior in the specific experimental situations. Hypophysial portal blood contains enriched concentrations of β-endorphin, but evidence for any EOP as a hypophysiotrophic neurohormone is equivocal. Galanin is colocalized in the central nervous system (CNS) with the following neuropeptides and neurohormones: Neuropeptide Y, Cholecystokinin, growth hormone-releasing hormone, luteinizing hormone-releasing hormone, and vasopressin. Substance P in the CNS was the first of the brain-gut peptides to be discovered due to its wide distribution, but it is considered primarily as a neuropeptide without significant non-neural digestive functions.