Evolution of angiotensin II-induced catecholamine release.

The interaction between angiotensin II (ANG II) and catecholamines was examined in nonmammalian vertebrates. ANG II challenge caused a significant pressor response in representatives of the seven vertebrate classes. Additionally, plasma levels of both epinephrine and norepinephrine increased following intravascular ANG II injection in the conscious lumpfish, bullfrog, and turtle, and the anesthetized chicken. Phentolamine pretreatment totally abolished ANG II pressor action in the hagfish and chicken and diminished the ANG II pressor response in other classes of vertebrates. The ability of ANG II to release catecholamines appears to be a phylogenetically ancient interaction and indicates that catecholamines may play an important role in the physiological expression of ANG II action in lower vertebrates.