INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
artículos
Título:
Beta-endorphinergic system involvement in the inhibitory action of clonidine on induced sodium appetite
Autor/es:
X.E. CAEIRO, A. GODINO, L. VIVAS
Revista:
REGULATORY PEPTIDES
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2011 vol. 167 p. 222 - 226
ISSN:
0167-0115
Resumen:
In the present study, we investigated the degree to which â-endorphin plays a role in the alpha 2-adrenergic/ imidazoline receptor agonist attenuation of salt appetite. In order to evaluate whether the inhibitory action of clonidine (an - alpha adrenergic/imidazoline receptor agonist) on induced sodium intake is mediated by the beta- endorphinergic system, we used a beta-endorphin deficient mouse line.beta-endorphin knockout (bend−/−), heterozygous (bend+/−) and wild-type (bend+/+)mice were submitted to acute sodium depletion by a combined treatment of furosemide and low sodium diet and, 20 h later,were administered with clonidine (0.5 mg/kg). An hour later, the animals were subjected to a two-bottle choice test (water/2% NaCl). The results indicate that clonidine administration during the first stage of the test exerts an equivalent inhibition on sodium intake regardless of the genotype; however, in the final stage of the test, a reversal of the inhibitory response on induced sodium appetite becomes evident in the mice lacking beta-endorphin. Moreover no differences in dipsogenic response were observed between the genotypes. Considering these results and the fact that plasma half-life of clonidine at the dose administered is approximately 3 h, it is possible to speculate that the inhibitory effect of clonidine on sodium appetite may be independent of beta-endorphin modulation during the first stage; however, the long-lasting inhibitory effect of clonidine may be mediated by the beta-endorphinergic system. This evidence supports the existence of adrenergic and clonidine may be mediated by the beta-endorphinergic system.