Resumo

HOCHT, Christian et al. Hypothalamic Effects of Angiotensin (1-7) in Rats with Aortic Coarctation. Rev. argent. cardiol. [online]. 2005, vol.73, n.5, pp.346-351. ISSN 1850-3748.

The objective of the present study was to evaluate the effect of the intrahypothalamic administration of angiotensin-[1-7] (Ang-[1-7]) on blood pressure and heart rate and on angiotensin II (Ang-II) activity in rats with sham operation (SO) and rats with aortic coarctation (ACo) in early and chronic stage of hypertension. Wistar rats were used. Seven and 42 days after the corresponding operation one carotid artery was cannulated for the measurement of the mean arterial pressure (MAP) in anaesthetized rats and an injection needle was inserted in the anterior hypothalamus by means of a stereotactic frame for the administration of Ang-II (50 ng), Ang-[1-7] (50 ng) and Ang-II + Ang-[1-7] (50 + 50 ng). Hypothalamic administration of Ang-II produced an increased MAP in the ACo rats when compared to the control group in the early and chronic stages of hypertension, whereas Ang-[1-7] did not induce significant changes in any experimental group. The co-administration of Ang -[1-7] reduced the pressure activity of the Ang-II in both early and chronic stages of hypertension in the ACo rats, whereas it had no effect on the pressure activity of Ang-II in the normotensive rats. In conclusion, the pressure activity of Ang-II is increased in rats with early and chronic stages of arterial hypertension. The antagonistic effect of Ang-[1-7] may indicate that this peptide could modulate the pressure activity of an already increased Ang-II, since it has been only observed in the hypertensive rats.

Palavras-chave : Aortic coarctation; Anterior hypothalamus; Arterial pressure; Angiotensin-[1-7]; Angiotensin II.

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