AJP - Regulatory, Integrative and Comparative Physiology, Vol 240, Issue 3 139-R143, Copyright © 1981 by American Physiological Society
Vascular response of the dogfish and sculpin to angiotensin II
R. G. Carroll
The mechanism by which angiotensin II (AII) exerts its pressor effect was
examined in a saltwater teleost and elasmobranch. In vivo application of
AII failed to elicit any changes in dogfish (Squalus acanthias) mesenteric
microcirculatory blood flow, but the sculpin (Myoxocephalus
octodecimspinosus) mesentery bed showed consistent reversible decreases in
blood flow following AII application. Topical treatment with 0.5 mg
phentolamine did not attenuate the AII response. In vitro addition of AII
did not alter the mean resting tension of the dogfish celiac artery or
intestinal vein, but significantly contracted the sculpin aorta. Addition
of chromaffin tissue to the dogfish arterial muscle bath imparted
significant vasoaction to AII when compared to saline. Both in vivo and in
vitro experiments demonstrate the absence of functional AII vascular
receptors in dogfish and their presence in the sculpin. Additional evidence
for the mediation of AII vascular action in the dogfish by catecholamine
release has been demonstrated.
