Detection of recombinant and endogenous mouse melatonin receptors by monoclonal antibodies targeting the C‐terminal domain

Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT₁ and MT₂, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT₁ and MT₂. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT₁ and MT₂ by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT₁ or MT₂. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT₂ expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.     

Body image,body dissatisfaction and weight status of Pacific adolescents from different ethnic communities: a cross-sectional study in New Caledonia

ABSTRACT

Objective(s): The prevalence of adolescent obesity is high among the various ethnic groups native to the Pacific region (European, Melanesian and Polynesian). An important factor of weight gain or loss is body size satisfaction; however, little is known about adolescent body self-perception in the Pacific region.

Design: Body dissatisfaction was evaluated using the Stunkard Figure Rating Scale in a sample of 699 adolescents from rural and urban areas of New Caledonia. The socio-demographic factors associated with higher body dissatisfaction were determined by multiple linear regression modeling.

Results: Our results showed a high rate of body dissatisfaction (over 70%) in the adolescents. Body dissatisfaction was strongly related to the body mass index z-score. Melanesians boys had higher body dissatisfaction scores when they felt ‘too thin’ while Melanesian girls showed lower body dissatisfaction when they felt ‘too fat.’.

Conclusion: These results showed that social pressure for thinness or musculature may be different among adolescents living in New Caledonia. These results should be taken into account in education overweight prevention programs.     

Intracellular Phosphate and ATP Depletion Measured by Magnetic Resonance Spectroscopy in Patients Receiving Maintenance Hemodialysis

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