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Published on: September 28, 2015
Evolution of angiotensin II-induced catecholamine release
The American Journal of Physiology
|July 1, 1982
Summary
Angiotensin II (ANG II) triggers a blood pressure increase and releases catecholamines like epinephrine and norepinephrine across diverse vertebrate classes. This ancient interaction suggests catecholamines are vital for ANG II
Area of Science:
- Comparative physiology
- Endocrinology
- Vertebrate biology
Background:
- Angiotensin II (ANG II) is a key hormone in regulating blood pressure and fluid balance.
- The role of ANG II and its interaction with catecholamines in nonmammalian vertebrates is not fully understood.
Purpose of the Study:
- To investigate the pressor response to ANG II across various vertebrate classes.
- To examine the effect of ANG II on plasma catecholamine levels (epinephrine and norepinephrine).
- To determine the role of catecholamines in mediating ANG II's physiological actions in lower vertebrates.
Main Methods:
- Intravascular injection of ANG II in representatives from seven vertebrate classes.
- Measurement of plasma epinephrine and norepinephrine levels post-ANG II administration.
- Assessment of ANG II pressor response following phentolamine (alpha-adrenergic antagonist) pretreatment.
Main Results:
- ANG II induced a significant pressor response in all seven vertebrate classes studied.
- Plasma epinephrine and norepinephrine levels increased after ANG II injection in lumpfish, bullfrog, turtle, and chicken.
- Phentolamine pretreatment abolished or diminished the ANG II-induced pressor response, highlighting catecholamine involvement.
Conclusions:
- The interaction between ANG II and catecholamines is a conserved, ancient physiological mechanism across vertebrates.
- Catecholamines are crucial mediators of ANG II's pressor effects in nonmammalian vertebrates.
- This study underscores the significant role of catecholamines in the physiological actions of ANG II in lower vertebrates.
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