Faculty Collaboration Database

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 2008 Mar;294(3):R1061-7

Date

01/11/2008

Pubmed ID

18184759

DOI

10.1152/ajpregu.00698.2007

Scopus ID

2-s2.0-40449104736 (requires institutional sign-in at Scopus site)   29 Citations

Abstract

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 (>2 wk) adaptation to these three protocols on blood volume (51Cr red cell space), extracellular fluid volume (99mTc-diethylene triaminepenta-acetic acid space), arterial (dorsal aortic; P(DA)) 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, P(DA), Pven, and mean circulatory filling pressure progressively increased in the order SW < FW < 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.

Author List

Olson KR, Hoagland TM

MESH terms used to index this publication - Major topics in bold

Adaptation, Physiological
Animals
Aorta, Thoracic
Blood Pressure
Blood Volume
Body Fluid Compartments
Diet
Fresh Water
Homeostasis
Oncorhynchus mykiss
Seawater
Sodium Chloride, Dietary
Vascular Capacitance
Water-Electrolyte Balance