Key result
Angiotensin II produced a dose-dependent increase in arterial pressure in embryonic chickens, with the maximal hypertensive response increasing from 31% on day 13 to 66% on day 21.
Why the study?
Does Angiotensin II regulate cardiovascular function (arterial pressure and heart rate) in developing embryonic chickens?
Does Angiotensin II regulate cardiovascular function (arterial pressure and heart rate) in developing embryonic chickens?
Angiotensin II plays an important role in the cardiovascular development of embryonic chickens, producing a dose-dependent hypertensive response that increases in intensity as development progresses.
Increases understanding of RAS maturation in avian embryos; leaves open relevance to mammalian cardiovascular development.
Angiotensin II (Ang II) is an important regulator of cardiovascular function in adult vertebrates. Although its role in regulating the adult system has been extensively investigated, the cardiovascular response to Ang II in embryonic vertebrates is relatively unknown. We investigated the potential of Ang II as a regulator of cardiovascular function in embryonic chickens, which lack central nervous system control of cardiovascular function throughout the majority of incubation. The cardiovascular response to Ang II in embryonic chickens was investigated over the final 50% of their development. Ang II produced a dose-dependent increase in arterial pressure on each day of development studied, and the response increased in intensity as development progressed. The Ang II type-1 receptor nonspecific competitive peptide antagonist [Sar1 ile8] Ang II blocked the cardiovascular response to subsequent injections of Ang II on day 21 only. The embryonic pressure response to Ang II (hypertension only) differed from that of adult chickens, in which initial hypotension is followed by hypertension. The constant level of gene expression for the Ang II receptor, in conjunction with an increasing pressure response to the peptide, suggests that two Ang II receptor subtypes are present during chicken development. Collectively, the data indicate that Ang II plays an important role in the cardiovascular development of chickens; however, its role in maintaining basal function requires further study.
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Crossley et al. (2010) studied Embryonic cardiovascular development (n=170). Angiotensin II vs. Baseline/Control was evaluated on Change in mean arterial pressure (Pmean) (p=<0.05). Angiotensin II produced a dose-dependent increase in arterial pressure in embryonic chickens, with the maximal hypertensive response increasing from 31% on day 13 to 66% on day 21.
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