Search results for "melanocortin"

Analysis of the melanocortin receptor 1 (MC1R) gene in Sicilian goat breeds

2010

AbstractMammalian coat colour is mainly determined by the distribution of two different types of melanins: pheomelanin (red/yellow pigments) and eumelanin (black pigments). Their synthesis is regulated by the melanocortin 1 receptor (MC1R/Extension locus) that binds the α-melanocyte-stimulating hormone (α-MSH) and the agouti signalling protein (ASIP, coded by the Agouti locus). In mammals, several studies have reported that loss-of-function mutations in MC1R lead to red/yellow pigmentation, while gain-of-function mutations lead to black/dark colours. Mutations at the Agouti locus exert, in general, epistatic interactions on the Extension locus. In goats, classical genetic studies have indic…

Coat colours in the Massese sheep breed are associated with mutations in the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes

2012

Massese is an Italian dairy sheep breed characterized by animals with black skin and horns and black or apparent grey hairs. Owing to the presence of these two coat colour types, this breed can be considered an interesting model to evaluate the effects of coat colour gene polymorphisms on this phenotypic trait. Two main loci have been already shown to affect coat colour in sheep: Agouti and Extension coding for the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes, respectively. The Agouti locus is affected by a large duplication including the ASIP gene that may determine the Agouti white and tan allele (A(Wt)). Other disrupting or partially inactivating mutations ha…

Sequence characterization of the melanocortin 1 receptor (MC1R) gene in sheep with different coat colour and identification of the putative e allele …

2010

Abstract Sequence of the melanocortin 1 receptor (MC1R) gene (the Extension locus) was obtained from a panel of 73 animals belonging to 9 Italian sheep breeds or populations (Appenninica, Bergamasca, Comisana, Cornigliese-like, Delle Langhe, Massese, Merinizzata Italiana, Sarda and Valle del Belice) with different coat colours. Evaluation of the identified polymorphisms on this phenotype was reported with in silico predictions and comparative approaches within and across breeds and across species. Five novel single nucleotide polymorphisms (SNPs), organized in three haplotypes, were detected. Another haplotype, including the two missense mutations already described for the ED allele, was id…

Unusual genomic structure: melanocortin receptors in Fugu.

2005

The melanocortin (MC) receptors are found in five subtypes in mammals and chicken, while recent studies have shown that the Fugu (Takifugu rubripes) genome has only four MC receptors and the zebrafish genome has six subtypes. The MC3 receptor seems to be missing from the two closely related pufferfishes, Fugu and Tetraodon (Tetraodon nigroviridis). The MC2 and MC5 receptors in the pufferfish have introns. Moreover, these two receptors are found in a tandem that is remarkably conserved in several vertebrate species. Here, we speculate about the genomic origin of the MC receptors.

Functional Evaluation of THIQ, a Melanocortin 4 Receptor Agonist, in Models of Food Intake and Inflammation

2007

The central melanocortinergic system plays an important role in regulating different aspects of energy homeostasis and the immunomodulatory response. In the present study, we evaluated the in vivo activities of food intake suppression and anti-inflammatory activity of THIQ, which has been proposed to possess high and selective melanocortin-4 receptor agonistic activity in vitro. The results showed that THIQ (0.1, 0.3 and 1 nmol/rat, intracerebroventricularly) is less effective in reducing food intake and body weights of rats than the non-selective melanocortin receptor agonist melanotan II. Electron paramagnetic resonance measurements in mice brain tissue showed that THIQ at doses of 0.001 …

Beta- and gamma-melanocortins inhibit lipopolysaccharide induced nitric oxide production in mice brain.

2003

The pro-opiomelanocortin-derived peptide alpha-melanocyte stimulating hormone (alpha-MSH) mediates many diverse physiological actions, including anti-inflammatory and immunomodulatory effects. However, little is known about the physiological roles of the other melanocortins, beta- and gamma-MSH. Here, we investigated the effects of melanocortin peptides in an in vivo neuroinflammation model. Six hours following intracisternal (i.c.) administration of 10 microg lipopolysaccharide (LPS) to mice a five-fold increase in the nitric oxide (NO) level was seen in the animals' brains, when detected by electron paramagnetic resonance (EPR). All tested melanocortins, alpha-, beta-, gamma1- and gamma2-…

Beta-MSH inhibits brain inflammation via MC(3)/(4) receptors and impaired NF-kappaB signaling.

2005

The anti-inflammatory effects of melanocortin peptides have been demonstrated in different inflammation models. This is the first report describing the molecular mechanisms for the beta-MSH-induced suppression of bacterial lipopolisaccharide (LPS)-caused brain inflammation. We found that beta-MSH suppresses LPS-induced nuclear translocation of the transcription factor NF-kappaB, and inhibits the expression of inducible nitric oxide synthase, and the following nitric oxide overproduction in the brain, in vivo. Moreover, administering the preferentially MC(4) receptor selective antagonist HS014 blocked completely these effects, suggesting a tentative MC(4) receptor mediated mechanism of actio…

Sex and MC1R variants in human pigmentation: Differences in tanning ability and sensitivity to sunlight between sexes

2016

Melanocortin receptor agonists MCR1-5protect photoreceptors from high-glucose damage and restore antioxidant enzymes in primary retinal cell culture

2016

Retinal photoreceptors are particularly vulnerable to local high-glucose concentrations. Oxidative stress is a risk factor for diabetic retinopathy development. Melanocortin receptors represent a family of G-protein-coupled receptors classified in five subtypes and are expressed in retina. Our previous data indicate that subtypes 1 and 5 receptor agonists exert a protective role on experimental diabetic retinopathy. This study focuses on their role in primary retinal cell cultures in high-glucose concentrations. After eye enucleation from wild-type male C57BL/6 mice, retinal cells were isolated, plated in high-glucose concentration and treated with melanocortin receptors 1 and 5 agonists an…

Transient Receptor Potential Canonical 3 (TRPC3) Channels Are Required for Hypothalamic Glucose Detection and Energy Homeostasis

2017

Fil: Chrétien, Chloé. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Fenech, Claire. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Liénard, Fabienne. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Grall, Sylvie. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Chevalier, Charlène. University of …