Canadian Medical Guide > Chemicals and Drugs > Amino Acids, Peptides, and Proteins > Peptides > Neuropeptides Terms and Definitions

Neuropeptides

Medical Definition:	Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.
Guide Notes:	GEN or unspecified; prefer specifics
Previously Indexed:	Nerve Tissue Proteins (1966-1986)

Neuropeptides Categories.

	Angiotensins - Oligopeptides ranging in size from angiotensin precursors with 14 amino acids to the active vasoconstrictor angiotensin II with 8 amino acids, or their analogs or derivatives. The amino acid content varies with the species and changes in that content produce antagonistic or inactive compounds.
	Calcitonin Gene-Related Peptide - Calcitonin gene-related peptide. A 37-amino acid peptide derived from the calcitonin gene. It occurs as a result of alternative processing of mRNA from the calcitonin gene. The neuropeptide is widely distributed in neural tissue of the brain, gut, perivascular nerves, and other tissue. The peptide produces multiple biological effects and has both circulatory and neurotransmitter modes of action. In particular, it is a potent endogenous vasodilator.
	Carnosine - A naturally occurring dipeptide neuropeptide found in muscles.
	Delta Sleep-Inducing Peptide - A nonapeptide that is found in neurons, peripheral organs, and plasma. This neuropeptide induces mainly delta sleep in mammals. In addition to sleep, the peptide has been observed to affect electrophysiological activity, neurotransmitter levels in the brain, circadian and locomotor patterns, hormonal levels, psychological performance, and the activity of neuropharmacological drugs including their withdrawal.
	FMRFamide - A molluscan neuroactive peptide which induces a fast excitatory depolarizing response due to direct activation of amiloride-sensitive SODIUM CHANNELS. (From Nature 1995; 378(6558): 730-3)
	Galanin - A 29-amino acid peptide that is found in both the central and peripheral nervous systems. It inhibits glucose-induced insulin release, hippocampal acetylcholine release, hippocampal glutamate (but not GAMMA-AMINOBUTYRIC ACID) release, and it lowers spinal excitability and firing of locus coeruleus neurons. It stimulates food (fat) intake and growth hormone release upon hypothalamic or i.c.v. injection. (Crit Rev Neurobiol 1993;7(3-4):229-74)
	Galanin-Like Peptide - A neuropeptide that is highly homologous to GALANIN. It is produced by proteolytic processing of a larger protein that is unrelated to prepro-galanin and preferentially binds to GALANIN RECEPTOR 2.
	Neuropeptide Y - A 36-amino acid peptide present in many organs and in many sympathetic noradrenergic neurons. It has vasoconstrictor and natriuretic activity and regulates local blood flow, glandular secretion, and smooth muscle activity. The peptide also stimulates feeding and drinking behavior and influences secretion of pituitary hormones.
	Neurophysins - A group of small, soluble proteins secreted by the hypothalamus. They serve as binding proteins for oxytocin and vasopressin during their transport to the posterior pituitary. They are secreted with the hormones but have no known functions other than serving as a carrier.
	Neurotensin - A biologically active tridecapeptide isolated from the hypothalamus. It has been shown to induce hypotension in the rat, to stimulate contraction of guinea pig ileum and rat uterus, and to cause relaxation of rat duodenum. There is also evidence that it acts as both a peripheral and a central nervous system neurotransmitter.
	Opioid Peptides - The endogenous peptides with opiate-like activity. The three major classes currently recognized are the ENKEPHALINS, the DYNORPHINS, and the ENDORPHINS. Each of these families derives from different precursors, proenkephalin, prodynorphin, and pro-opiomelanocortin, respectively. There are also at least three classes of opioid receptors, but the peptide families do not map to the receptors in a simple way.

Neuropeptides Medical Definitions and Terms

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