Cardiovascular and renal effects of eel and rat atrial natriuretic peptide in rainbow trout, Salmo gairdneri

Olson, Kenneth R.; Duff, Douglas W.

doi:10.1007/bf00258962

Cited by 27 publications

(13 citation statements)

References 20 publications

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“…These studies confirm previous observations that trout P DA falls when trout are adapted from FW to SW (24) and increases when FW fish are fed a HS diet (5,9). There is accumulating evidence that both FW-to-SW transfer and HS diet are associated with a salt overload.…”

Section: Discussionsupporting

confidence: 89%

Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout

Olson¹,

Hoagland²

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Olson KR, Hoagland TM. Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout. Am J Physiol Regul Integr Comp Physiol 294: R1061-R1067, 2008. First published January 9, 2008 doi:10.1152/ajpregu.00698.2007.-Trout are of interest in defining the relationship between fluid and salt balance on cardiovascular function because they thrive in freshwater (FW; volume loading, salt depleting), saltwater (SW; volume depleting, salt loading), and FW while fed a high-salt diet (FW-HS; volume and salt loading). The effects of chronic (Ͼ2 wk) adaptation to these three protocols on blood volume ( 51 Cr red cell space), extracellular fluid volume ( 99m Tc-diethylene triaminepenta-acetic acid space), arterial (dorsal aortic; PDA) and venous (ductus Cuvier; Pven) blood pressure, mean circulatory filling pressure (zero-flow Pven), and vascular capacitance were examined in the present study on unanesthetized rainbow trout. Blood volume, extracellular fluid volume, PDA, Pven, and mean circulatory filling pressure progressively increased in the order SW Ͻ FW Ͻ FW-HS. Vascular capacitance in SW fish appeared to be continuous with the capacitance curve of FW fish and reflect a passive volume-dependent unloading of the venous system of FW fish. Vascular capacitance curves for FW-HS fish were displaced upward and parallel to those of FW fish, indicative of an active increase in unstressed blood volume without any change in vascular compliance. These studies are the first in any vertebrate to measure the relationship between fluid compartments and cardiovascular function during independent manipulation of volume and salt balance, and they show that volume, but not salt, balance is the primary determinant of blood pressure in trout. They also present a new paradigm with which to investigate the relative contributions of water and salt balance in cardiovascular homeostasis. fish; unstressed blood volume; mean circulatory filling pressure; osmoregulation; ionoregulation THE PIONEERING STUDIES OF Goldblatt et al. (13), Guyton et al. (15), Dahl and Heine (8), and others clearly showed that salt and water balance were primary effectors of blood pressure in mammals. Although a direct effect of salt balance on blood pressure has been suggested (2), it is generally accepted that fluid volume is the primary effector of blood pressure and that salt balance is regulated to maintain fluid volume. This is not surprising, as water loss in the urine or through evaporation is a chronic problem for terrestrial vertebrates, and, because water is not actively transported, it can only be retained if osmotically coupled to an osmolyte, usually salt. However, the inexorable coupling of water and salt has been problematic in understanding the pathophysiology of blood pressure regulation (2, 19, 35).The relative impact of volume regulation and salt balance on blood pressure regulation in fish may be more amenable to experimentation. Saltwater (SW) fish live in an environment with a ...

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Section: Discussionsupporting

confidence: 89%

Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout

Olson¹,

Hoagland²

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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“…183,206,553,559), and ANP decreased gill resistance in the rainbow trout in vivo (550), corroborating an earlier study that demonstrated that ANP decreased arterio-arterial resistance in the epinephrine-contracted, perfused gills from that species (559). Unfortunately, no in vivo videomicroscopy studies have been done to visualize the effects of NPs on gill blood flow directly.…”

Section: Natriuretic Peptidessupporting

confidence: 70%

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

Evans¹,

Piermarini²,

Choe³

2005

Physiological Reviews

2,325

1,788

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The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes. Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates. Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself. The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system. Nevertheless, substantial questions about the evolution of these mechanisms and control remain.

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“…With respect to the renal action of ANP, the initial studies using mammalian ANP or homologous heart extracts resulted in potent diuretic and natriuretic effects in the rainbow trout (21,66) and toadfish, Opsanus tau (49). Because the toadfish has an aglomeru- lar kidney, the data provided the first direct evidence of the tubular action of ANP in vertebrates.…”

Section: Osmoregulatory Actions Of Anp In Fish Other Than Eelsmentioning

confidence: 98%

The natriuretic peptide system in eels: a key endocrine system for euryhalinity?

Takei

Hirose

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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Takei, Yoshio, and Shigehisa Hirose. The natriuretic peptide system in eels: a key endocrine system for euryhalinity? Am J Physiol Regulatory Integrative Comp Physiol 282: R940-R951, 2002; 10.1152/ajpregu. 00389.2001.-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 Ctype 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 ϩ and water in mammals, ANP more specifically extrudes Na ϩ 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 ϩ 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 ϩ 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 22 Na 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 ATRIAL NATRIURETIC PEPTIDE (ANP) was the first member of the natriuretic peptide (NP) family identified in mammals (17,63,69,86). Subsequent to the isolation and sequencing of ANP from the rat atria in 1983, brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) were isolated from the porcine brain in 1988 and 1990, respectively, and they were identified as members of the NP family (Fig. 1). Whereas ANP and BNP are circulating hormones secreted from the heart, CNP is principally a paracrine factor in the brain and periphery (71). The basic structure of the NP peptides consists of an intramolecular...

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Cardiovascular and renal effects of eel and rat atrial natriuretic peptide in rainbow trout, Salmo gairdneri

Cited by 27 publications

References 20 publications

Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout

Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

The natriuretic peptide system in eels: a key endocrine system for euryhalinity?

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