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1.
Endocrinology ; 149(1): 310-9, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17901225

RESUMO

We previously described a colocalization between arginine vasopressin (AVP) and the chemokine stromal cell-derived factor-1alpha (SDF-1) in the magnocellular neurons of both the hypothalamic supraoptic and paraventricular nucleus as well as the posterior pituitary. SDF-1 physiologically affects the electrophysiological properties of AVP neurons and consequently AVP release. In the present study, we confirm by confocal and electron microscopy that AVP and SDF-1 have a similar cellular distribution inside the neuronal cell and can be found in dense core vesicles in the nerve terminals in the posterior pituitary. Because the Brattleboro rats represent a good model of AVP deficiency, we tested in these animals the fate of SDF-1 and its receptor CXCR4. We identified by immunohistochemistry that both SDF-1 and CXCR4 immunoreactivity were strongly decreased in Brattleboro rats and were strictly correlated with the expression of AVP protein in supraoptic nucleus, paraventricular nucleus, and the posterior pituitary. We observed by real-time PCR an increase in SDF-1 mRNA in both heterozygous and homozygous rats. The effect on the SDF-1/CXCR4 system was not linked to peripheral modifications of kidney water balance because it could not be restored by chronic infusion of deamino-8D-ariginine-vasopressin, an AVP V2-receptor agonist. These original data further suggest that SDF-1 may play an essential role in the regulation of water balance.


Assuntos
Quimiocina CXCL12/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Vasopressinas/fisiologia , Animais , Animais Geneticamente Modificados , Água Corporal/metabolismo , Água Corporal/fisiologia , Quimiocina CXCL12/genética , Quimiocina CXCL12/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Homeostase/genética , Homeostase/fisiologia , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Hipotálamo/química , Hipotálamo/metabolismo , Masculino , Neuro-Hipófise/metabolismo , RNA Mensageiro/análise , Ratos , Ratos Brattleboro , Ratos Long-Evans , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Frações Subcelulares/metabolismo , Distribuição Tecidual , Vasopressinas/metabolismo , Vasopressinas/farmacologia
2.
Physiol Behav ; 75(1-2): 41-7, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-11890951

RESUMO

The aim of this study was to determine the effects of the chronic ingestion of aspartame (ASP) on brain neuropeptide Y (NPY) concentrations, plasma hormones, food intake and body fat. Two groups of male Long-Evans rats, fed on a control (C) well-balanced diet, had to drink either a 0.1% ASP solution or water for a period of 14 weeks starting at weaning. Food intake and body weight were weekly recorded. At the end of the experiment, fat pads were sampled, leptin and insulin were measured in the plasma and NPY in several microdissected brain areas. Substituting ASP for water led to lower body weight (-8%; P<.004) and lower fat depot weight (-20%; P<.01) with no differences in energy intake or plasma insulin concentrations. Plasma leptin was significantly reduced by 34% (P<.05). Leptin concentrations were well-correlated with final body weight (r=.47; P<.025) and fat pad mass (r=.53; P<.01). NPY concentrations were 23% lower (P<.03) in the arcuate nucleus of ASP rats with no differences in other brain areas. The beneficial effects on body composition could be related to the decreased effects of NPY on lipid and energy metabolism, independently of insulin. The reasons for the NPY decrease (regulatory or toxicological) are not obvious. The constitutive amino acids of the ASP molecule might participate in the NPY regulation.


Assuntos
Aspartame/farmacologia , Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Hipotálamo/metabolismo , Leptina/sangue , Neuropeptídeo Y/metabolismo , Edulcorantes/farmacologia , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/crescimento & desenvolvimento , Animais , Glicemia/metabolismo , Química Encefálica/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Crescimento/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Masculino , Ratos , Ratos Long-Evans
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