Corpuscles of Stannius secrete renin or an isorenin that regulates cardiovascular function in freshwater North American eels, Anguilla rostrata LeSueur.
Dorsal aortic blood flow (DABF) and caudal venous blood flow (CVBF) were measured in free-swimming conscious freshwater (FW) North American eels (Anguilla rostrata) with Doppler-flow probes. DABF and CVBF increased in a dose-dependent manner following iv doses of [Asn(1), Val(5), Gly(9)]-angiotensin I (ANG I), [Asn(1), Val(5)]-angiotensin II (ANG II), and [Val(4)]-angiotensin III (ANG III) ranging from 5 to 50 ng x kg bw(-1). A minimum effective dose for ANG I and ANG II was 5 ng x kg bw(-1); that for ANG III was 10 ng x kg bw(-1). DABF and CVBF rates increased during the first 2 min and remained elevated for 20-50 min. Flow responses similar to those of ANG II in form and magnitude followed iv injections of extracts of corpuscles of Stannius (CS-EXT). Increases in DABF and CVBF following injections of ANG I, human renin substrate (hRS), and CS-EXT were all blocked by the angiotensin-converting enzyme inhibitor Captopril. Increases in DABF and CVBF which followed injections of hRS and CS-EXT were blocked completely by pepstatin A. [Sar(1), Val(5)]-ANG II (Sarile) blocked completely the DABF and CVBF responses to ANG II and CS-EXT, but the mammalian receptor antagonists losartan (AT1) and PD123319 (AT2) only partially blocked them. These findings support strongly the hypothesis that the corpuscles of Stannius secrete renin or isorenin and that the renin-angiotensin system regulates cardiovascular function in freshwater eels and other bony fishes that possess them.
Butler
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DG
Department of Zoology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.
Zhang
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DH
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000809:Angiotensins / Q000494:pharmacology*; D000811:Anguilla / Q000502:physiology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology*; D002216:Captopril / Q000494:pharmacology; D004702:Endocrine Glands / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D019808:Losartan / Q000494:pharmacology; D010436:Pepstatins / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012083:Renin / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology*; D018608:Ultrasonography, Doppler; D000092502:Renin Inhibitors
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D000889:Anti-Arrhythmia Agents; D002216:Captopril; D007093:Imidazoles; D019808:Losartan; D010436:Pepstatins; D011480:Protease Inhibitors; D011725:Pyridines; D012083:Renin; D000092502:Renin Inhibitors; C073402:PD 123319; C031375:pepstatin