Diseases, Conditions, Syndromes

What autoimmune diseases are and what can be done to alleviate them

If you have celiac disease, inadvertently consuming even a single crumb of bread can lead to gastrointestinal upset for weeks or months. For those who suffer from lupus, a flare can damage kidneys—or even worse. People ...

Medical research

When injured muscles mistakenly grow bones

For hundreds of thousands of people, injuring a muscle through an accident like falling off a bike or having surgery can result in a strange and serious complication. Their muscles start growing bones.

Medical research

New brain target for appetite control identified

Researchers at Columbia University Medical Center (CUMC) have identified a brain receptor that appears to play a central role in regulating appetite. The findings, published today in the online edition of Cell, could lead ...

Neuroscience

Neurons can use local stores for communication needs

Researchers reveal that neurons can utilize a supremely localized internal store of calcium to initiate the secretion of neuropeptides, one class of signaling molecules through which neurons communicate with each other and ...

Neuroscience

Maintaining wakefulness: The role of orexin neuropeptides

(Medical Xpress)—One of Kanazawa University's leading professors has spent the last 15 years investigating the role of orexin neuropeptides in the brain. Takeshi Sakurai's work is furthering understanding of sleep and wakeful ...

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Neuropeptide

Neuropeptides are small protein-like molecules used by neurons to communicate with each other. They are neuronal signaling molecules, influence the activity of the brain in specific ways and are thus involved in particular brain functions, like analgesia, reward, food intake, learning and memory.

Neuropeptides are expressed and released by neurons, and mediate or modulate neuronal communication by acting on cell surface receptors. The human genome contains about 90 genes that encode precursors of neuropeptides. At present about 100 different peptides are known to be released by different populations of neurons in the mammalian brain. Neurons use many different chemical signals to communicate information, including neurotransmitters, peptides, cannabinoids, and even some gases, like nitric oxide.

Many populations of neurons have distinctive biochemical phenotypes. For example, in one subpopulation of about 3000 neurons in the arcuate nucleus of the hypothalamus, three anorectic peptides are co-expressed: α-melanocyte-stimulating hormone (α-MSH), galanin-like peptide, and cocaine-and-amphetamine-regulated transcript (CART), and in another subpopulation two orexigenic peptides are co-expressed, neuropeptide Y and agouti-related peptide (AGRP). These are not the only peptides in the arcuate nucleus; β-endorphin, dynorphin, enkephalin, galanin, ghrelin, growth-hormone releasing hormone, neurotensin, neuromedin U, and somatostatin are also expressed in subpopulations of arcuate neurons. These peptides are all released centrally and act on other neurons at specific receptors. The neuropeptide Y neurons also make the classical inhibitory neurotransmitter GABA.

Invertebrates also have many neuropeptides. CCAP has several functions including regulating heart rate, allatostatin and proctolin regulate food intake and growth, bursicon controls tanning of the cuticle and corazonin has a role in cuticle pigmentation and moulting.

Peptide signals play a role in information processing that is different from that of conventional neurotransmitters, and many appear to be particularly associated with specific behaviours. For example, oxytocin and vasopressin have striking and specific effects on social behaviours, including maternal behaviour and pair bonding.

This text uses material from Wikipedia, licensed under CC BY-SA