کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2023397 1542451 2006 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Hypothalamic cardiovascular effects of angiotensin-(1–7) in spontaneously hypertensive rats
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Hypothalamic cardiovascular effects of angiotensin-(1–7) in spontaneously hypertensive rats
چکیده انگلیسی

The objective of the present work was to study the cardiovascular actions of the intrahypothalamic injection of Ang-(1–7) and its effects on the pressor response to Ang II in spontaneously hypertensive (SH) rats and Wistar Kyoto (WKY) animals. In anaesthetized SH and WKY rats, a carotid artery was cannulated for mean arterial pressure (MAP) measurement and a stainless-steel needle was inserted into the anterior hypothalamus for drug administration. The cardiovascular effects of the intrahypothalamic administration of Ang-(1–7) were determined in SH and WKY rats. In SH rats, the effect of irbesartan and d-Ala-Ang-(1–7) on Ang-(1–7) cardiovascular effect was also evaluated. Ang II was administered in the hypothalamus of SH and WKY rats and changes in blood pressure and heart rate were measured followed by the administration of Ang II, Ang II + Ang-(1–7) or Ang II + d-Ala-Ang-(1–7). Ang-(1–7) did not the change basal MAP in WKY rats, but induced a pressor response in SH animals. Whilst the co-administration of d-Ala-Ang-(1–7) did not affect the response to Ang-(1–7), the previous administration of irbesartan prevented the effect of the peptide. The intrahypothalamic injection of Ang II induced a significantly greater pressor response in SH animals compared to normotensive rats. The co-administration of Ang-(1–7) with Ang II did not affect the pressor response to Ang II in the WKY group. In SH rats, whilst the co-administration of Ang-(1–7) with Ang II reduced the pressor response to Ang II, the concomitant application of d-Ala-Ang-(1–7) with Ang II increased the pressor response to the octapeptide after 5 and 10 min of intrahypothalamic administration. In conclusion, our result demonstrated that the biologically active peptide Ang-(1–7) did not participate in the hypothalamic blood pressure regulation of WKY animals. In SH rats, Ang-(1–7) exerted pleiotropic effects on blood pressure regulation. High dose of the heptapeptide produced a pressor response because of an unspecific action by activation of AT1 receptors. The concomitant administration of lower doses of Ang-(1–7) with Ang II reduced the pressor response to the octapeptide. Finally, the effect of AT1–7 antagonist on Ang II pressor response suggested that hypothalamic formed Ang-(1–7) are implicated in the regulation of the cardiovascular effects of Ang II.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Regulatory Peptides - Volume 135, Issues 1–2, 15 July 2006, Pages 39–44
نویسندگان
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