Neuroregulatory peptides

Neuronal projections from the hypothalamus to other regions of the brain relay important output information that influence blood pressure, appetite, thirst, circadian rhythm, behavior, nociception (pain perception), and others factors. Although many of these neurons release neurotransmitter amines at synapses, some of them are known to release neurotransmitter peptides. These include, among others, peptides that closely resemble hormones formed in the gastrointestinal system as well as the endogenous opiates (Table 31-3). 

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Somatostatin is a neuroregulatory peptide secreted by the hypothalamus. Human somatostatin receptors (ssts) are expressed in the brain, anterior pituitary gland, pancreas, thyroid gland, and in the mucosa of the gastrointestinal tract (Hofland and Lamberts 1997 Patel 1999). Tumors arising from sst-positive cells in these organs contain a high density of ssts (Hofland et al. 2003 Lamberts et al. 1991 Reubi 1996). 

Date, Y., Ueta, Y., Yamashita, H. et al. (1999). Orexins, orexigenic hypothalamic peptides, interact with autonomic, neuroendocrine and neuroregulatory systems. Proc. Natl Acad. Sci. USA 96, 748-53. 

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