Neuropeptides modulation

Appetite-stimulating. Neuropeptide modulators and gut hormones with orexigenic effects are neuropeptide Y (NPY), agouti-related protein (AGRP), melaninconcentrating hormone (MCH), endocannabinoids, galanin, ghrelin and others. 

Muscettola, M. and Grasso, G. (1990). Neuropeptide modulation of interferon gamma production. Int. J. Neurosci. 51, 189-191. 

Chung, S., Civelli, O. Orphan neuropeptides. Novel neuropeptides modulating sleep or feeding. Neuropeptides 2006, 40, 233-243. 

Hong JS, Hung CR, Seth PK, et al. 1984. Effect of manganese treatment on the levels of neurotransmitters, hormones, and neuropeptides Modulation by stress. Environ Res 34 242-249. 

Nambu, J. R., Taussig, R., Mahon, A. C. and Scheller, R. H. (1983) Gene isolation with cDNA probes from identified Aplysia neurons neuropeptide modulators of cardiovascular physiology. Cell 35 47-56. 

Proctolin, H-Arg-Tyr-Leu-Pro-Thr-OH, a bioactive neuropeptide modulating in-terneuronal and neuromuscular synaptic transmissions in a wide variety of arthropods. It was discovered as an excitatory neurotransmitter from the intestinal musculature of insects. Extremely low concentrations (10 mol L ) cause violent contraction of the end of the gut. For the first isolation of proctolin, 125,000 cockroaches (Periplaneta americana) were required. Although proctolin was the first insect neuropeptide to be discovered, it is now regarded as the main neuromuscular trans-mitter/modulator in the gut of most insect species. In 2003, a G protein-coupled receptor for proctolin in Drosophila mdanogaster was identified and characterized [A. N. Star-ratt, B. E. Brown, Life Sci. 1975, 17, 1253 D. Konopihska, G. Rozihski, J. Peptide Sci. 1999, 5, 533 E. J. Johnson et al., Proc. Natl. Acad. Sci. USA 2003, 100, 6198]. 

Melanin-concentrating hormone (MCH) is a cyclic neuropeptide of 19 amino acids. It is involved in the modulation of feeding behavior. Its actions are mediated by G-protein coupled receptors (MCH1 and MCH2). 

Purinergic System. Figure 2 Schematic of sympathetic cotransmission. ATP and NA released from small granular vesicles (SGV) act on P2X and a-i receptors on smooth muscle, respectively. ATP acting on inotropic P2X receptors evokes excitatory junction potentials (EJPs), increase in intracellular calcium ([Ca2+]j) and fast contraction while occupation of metabotropic ar-adrenoceptors leads to production of inositol triphosphate (IP3), increase in [Ca2+]j and slow contraction. Neuropeptide Y (NPY) stored in large granular vesicles (LGV) acts after release both as a prejunctional inhibitory modulator of release of ATP and NA and as a postjunctional modulatory potentiator of the actions of ATP and NA. Soluble nucleotidases are released from nerve varicosities, and are also present as ectonucleotidases. (Reproduced from Burnstock G (2007) Neurotransmission, neuromodulation cotransmission. In Squire LR (ed) New encyclopaedia of neuroscience. Elsevier, The Netherlands (In Press), with permission from Elsevier). 

Several neurotransmitters and neuropeptides influence sleep-wakefulness, including REM sleep. Although NA-ergic and ACh-ergic influences have been studied more extensively, other neurotransmitters also play an important role in the modulation of REM sleep (Sakai, 1986 Mallick et al, 1999 Jones, 2005). 

Cortistatin a cortical neuropeptide with sleep-modulating activity... 

Neuropeptide S (NPS) is a recently discovered bioactive peptide that has emerged as a new signaling molecule in the complex circuitry that modulates sleep-wakefulness and anxiety-like behavior. The peptide precursor is expressed most prominently in a novel nucleus located in the perilocus coeruleus, a brain structure with well-defined functions in arousal, stress, and anxiety. NPS was also found to induce anxiolytic-like behavior in a battery of four different tests of innate responses to stress. Infusion of NPS potently increases wakefulness and suppresses non-REM (NREM) and REM sleep (Xu et al, 2004). NPS binds to a G-protein-coupled receptor, the NPS receptor, with nanomolar affinity activation of the receptor mobilizes intracellular calcium. The NPS receptor is expressed throughout the brain, particularly in regions relevant to the modulation of sleep and waking, in the tuberomammillary region, lateral hypothalamus, and medial thalamic nuclei. 

Multiple neurotransmitter systems are found in the basal ganglia. The basal ganglia contain most of the classical neurotransmitters, and many additional neuropeptides which may participate in the modulation of information transfer in the basal ganglia. Some of the more important systems will be discussed in the following paragraphs. 

Bouchard P, Roman F, Junien JL, Quirion R. 1996. Autoradiographic evidence for the modulation of in vivo sigma receptor labeling by neuropeptide Y and calcitonin gene-related peptide in the mouse brain. J Pharmacol Exp Ther 276 223-230. 

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