A new natriuretic peptide isolated from cardiac atria of trout, Oncorhynchus mykiss.
Atrial and brain natriuretic peptides (ANP and BNP, respectively) are two cardiac natriuretic peptides (NPs) found in tetrapods from amphibians to mammals, whereas ANP and ventricular NP (VNP) have been identified in eel hearts. Because VNP has also been found in the rainbow trout ventricle, we attempted to isolate NP from trout cardiac atria in order to determine whether ANP and VNP are common cardiac NPs in teleosts. In the present experiments, we isolated VNP and a novel atrial NP consisting of 29 amino acid residues from the atria. This new trout NP exhibited similar sequence identity to mammalian ANP and BNP (50-60%). Its homology to eel ANP was low (52%) compared with high homology of trout and eel VNP (78%). Based on yield, the content of this new NP in trout atria may be even smaller than that of VNP. The new trout atrial NP exhibited low relaxant activity in the chick rectum (only 1/10 of that of trout VNP), and extremely low vasorelaxant activity in the rat aortic strip (only 1/400 of that of human ANP). However, the new trout NP was equipotent with trout VNP and human ANP in relaxing trout epibranchial artery. Based on the sequence similarity with other NPs and on atrial content, the new NP isolated from trout atria cannot yet be assigned to a known member of the NP family.
Takei
Y
Y
Laboratory of Physiology, Ocean Research Institute, University of Tokyo, Nakano, Japan. takei@ori.u-tokyo.ac.jp
Fukuzawa
A
A
Itahara
Y
Y
Watanabe
T X
TX
Yoshizawa Kumagaye
K
K
Nakajima
K
K
Yasuda
A
A
Smith
M P
MP
Duff
D W
DW
Olson
K R
KR
D000595:Amino Acid Sequence; D000663:Amphibians; D000818:Animals; D001158:Arteries; D009320:Atrial Natriuretic Factor / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002645:Chickens; D004524:Eels; D006325:Heart Atria; D006352:Heart Ventricles; D006801:Humans; D008322:Mammals; D008969:Molecular Sequence Data; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D017686:Oncorhynchus mykiss; D011892:Rana catesbeiana; D051381:Rats; D012007:Rectum; D016415:Sequence Alignment; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents
D014665:Vasodilator Agents; C092435:ventricular natriuretic factor, rainbow trout; D009320:Atrial Natriuretic Factor