Maturation of the angiotensin II cardiovascular response in the embryonic White Leghorn chicken (Gallus gallus).
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 [Sar(1) ile(8)] 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.
Crossley
Dane A
DA
Department of Biology, University of North Dakota, 10 Cornell Street, Mail stop 9019, Grand Forks, ND 58202, USA. dane.crossley@und.nodak.edu
Jonker
Sonnet S
SS
Hicks
James W
JW
Thornburg
Kent L
KL
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002319:Cardiovascular System / Q000187:drug effects / Q000196:embryology*; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D047108:Embryonic Development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006321:Heart / Q000187:drug effects / Q000196:embryology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D047228:Angiotensin II Type 1 Receptor Blockers; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; D015059:1-Sarcosine-8-Isoleucine Angiotensin II