| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Ocean Research Institute, the University of Tokyo, Nakano-ku, Tokyo 164-8639; and 2 Department of Biological Sciences, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8501, Japan
The natriuretic peptide system of a euryhaline teleost, the Japanese eel (Anguilla japonica), consists of three types of hormones [atrial natriuretic peptide (ANP), ventricular natriuretic peptide (VNP), and C-type natriuretic peptide (CNP)] and four types of receptors [natriuretic peptide receptors (NPR)-A, -B, -C, and -D]. Although ANP is recognized as a volume-regulating hormone that extrudes both Na+ and water in mammals, ANP more specifically extrudes Na+ in eels. Accumulating evidence shows that ANP is secreted in response to hypernatremia and acts to inhibit the uptake and to stimulate the excretion of Na+ but not water, thereby promoting seawater (SW) adaptation. In fact, ANP is secreted immediately after transfer of eels to SW and ameliorates sudden increases in plasma Na+ concentration through inhibition of drinking and intestinal absorption of NaCl. ANP also stimulates the secretion of cortisol, a long-acting hormone for SW adaptation, whereas ANP itself disappears quickly from the circulation. Thus ANP is a primary hormone responsible for the initial phase of SW adaptation. By contrast, CNP appears to be a hormone involved in freshwater (FW) adaptation. Recent data show that the gene expression of CNP and its specific receptor, NPR-B, is much enhanced in FW eels. In fact, CNP infusion increases 22Na uptake from the environment in FW eels. These results show that ANP and CNP, despite high sequence identity, have opposite effects on salinity adaptation in eels. This difference apparently originates from the difference in their specific receptors, ANP for NPR-A and CNP for NPR-B. VNP may compensate the effects of ANP and CNP for adaptation to respective media, because it has high affinity to both receptors. On the basis of these data, the authors suggest that the natriuretic peptide system is a key endocrine system that allows this euryhaline fish to adapt to diverse osmotic environments, particularly in the initial phase of adaptation.
atrial natriuretic peptide; ventricular natriuretic peptide; C-type natriuretic peptide; membrane guanylyl cyclase; water and electrolyte balance; molecular evolution; functional evolution; volume regulation; sodium regulation; Anguilla japonica
This article has been cited by other articles:
|
|
 |
|
  K. R. Johnson and K. R. Olson Responses of the trout cardiac natriuretic peptide system to manipulation of salt and water balance Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2009; 296(4): R1170 - R1179. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Vierimaa, J. Ronkainen, H. Ruskoaho, and O. Vuolteenaho Synergistic activation of salmon cardiac function by endothelin and beta-adrenergic stimulation Am J Physiol Heart Circ Physiol, September 1, 2006; 291(3): H1360 - H1370. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. H. Evans, P. M. Piermarini, and K. P. Choe The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste Physiol Rev, January 1, 2005; 85(1): 97 - 177. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Y. Jin, J. F. Wen, D. Li, and K. W. Cho Osmoregulation of atrial myocytic ANP release: osmotransduction via cross-talk between L-type Ca2+ channel and SR Ca2+ release Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2004; 287(5): R1101 - R1109. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
