High fructose diet increases anterior hypothalamic alpha 2-adrenoceptors responsiveness.
Neurosci Lett
; 423(2): 128-32, 2007 Aug 16.
Article
em En
| MEDLINE
| ID: mdl-17683864
Activation of alpha(2)-adrenoceptors in the anterior hypothalamic area (AHA) decreases sympathetic nervous system activity and blood pressure. The aim of the present study was to evaluate activity of pre- and postsynaptic alpha(2)-adrenoceptors in the AHA of fructose hypertensive rats (F), an animal model of insulin resistance and hypertension. The AHA of Control (C) and F anaesthetized rats was perfused with Ringer solution in the absence or presence of clonidine (100 or 300 microg ml(-1)) using reverse microdialysis. Clonidine effects on mean arterial pressure (MAP) and heart rate (HR), and on hypothalamic noradrenaline levels were measured along perfusion time. Noradrenaline extracellular levels in the AHA were significantly diminished in F hypertensive rats compared to C animals. The depressor effect of intrahypothalamic perfusion of clonidine on MAP was enhanced in F rats compared with C animals. Intrahypothalamic perfusion of clonidine reduced HR only in F rats. The effect of clonidine on noradrenaline hypothalamic extracellular levels was enhanced in F rats. These results suggest, in our experimental conditions, the existence of an increased responsiveness of pre- and postsynaptic alpha(2)-adrenoceptors in the AHA of F hypertensive rats. This fact could be a consequence of a compensatory supersensitivity of alpha-adrenoceptors due to a decrease in noradrenaline release from nerve terminals located in the AHA.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hipotálamo Anterior
/
Resistência à Insulina
/
Receptores Adrenérgicos alfa 2
/
Frutose
/
Hipertensão
Limite:
Animals
Idioma:
En
Revista:
Neurosci Lett
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Irlanda