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Titolo:
Effects of hypoxia on isolated vessels and perfused gills of rainbow trout
Autore:
Smith, MP; Russell, MJ; Wincko, JT; Olson, KR;
Indirizzi:
Univ Notre Dame, S Bend Ctr Med Educ, Indiana Univ, Sch Med, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 Sch Med, Notre Dame, IN 46556 USA Univ Notre Dame, Dept Sci Biol, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 ci Biol, Notre Dame, IN 46556 USA
Titolo Testata:
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY
fascicolo: 1, volume: 130, anno: 2001,
pagine: 171 - 181
SICI:
1095-6433(200108)130:1<171:EOHOIV>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
ARTERIAL SMOOTH-MUSCLE; PULMONARY VASOCONSTRICTION; CHANNELS; LOCALIZATION;
Keywords:
fish; vascular tone; hypoxic vasodilation; hypoxic vasoconstriction; potassium channels;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Olson, KR Univ Notre Dame, S Bend Ctr Med Educ, Indiana Univ, Sch Med, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 otre Dame, IN 46556 USA
Citazione:
M.P. Smith et al., "Effects of hypoxia on isolated vessels and perfused gills of rainbow trout", COMP BIOC A, 130(1), 2001, pp. 171-181

Abstract

Local hypoxia dilates systemic and constricts pulmonary blood vessels in mammals without neural or humoral involvement. The direct effects of hypoxiaon isolated vessels from bony fish have not been examined. In the present study, isolated vessels (efferent branchial artery, EBA; coeliacomesentericartery, CMA; ventral aorta, VA; and anterior cardinal vein, ACV) from rainbow or steelhead trout (Oncorhynchus mykiss) were subjected to either passive load (resting tension) or contracted with a ligand or 50 mM KCI and thensubjected to 60 min of hypoxia by N-2 administration and an additional 30 min of normoxia. All vessels were usually refractory to hypoxia under conditions of resting tension. EBAs, CMAs and VAs pre-contracted with a receptor-mediated ligand were all significantly relaxed by hypoxia and only VAs recovered significantly upon subsequent restoration of normoxia. In contrast, tension in all arteries pre-contracted with 50 mM KCI was elevated further in response to hypoxia. Conversely, ligand-contracted ACVs responded to hypoxia with a further increase in tension, whereas KCI-contracted ACVs relaxed. During apparently random 2-3-week periods EBA and CMA from steelhead andEBA from rainbow trout were hyper-reactive to hypoxia. Steelhead vessels responded to hypoxia. with a rapid contraction that increased in magnitude over 3 days. These contractions were independent of pre-stimulation and theywere dose-dependent upon PO2. In isolated gills, hypoxic perfusate produced an immediate but transient elevation of resistance (R-GILL) in all four gill arches. R-GILL increased by as much as 30% of initial values and this response was unaltered upon a second hypoxic exposure. These studies demonstrate that isolated vascular segments of rainbow trout are indeed responsiveto hypoxia and that these differential responses are vessel and tone dependent and the overall response may be altered by as yet unknown seasonal or environmental factors. Hypoxia-induced arterial relaxation is blocked by elevated external [K+], implicating alteration of transmembrane K+ conductance and/or membrane potential in this depressor response. K+-channel closure or voltage-gated Ca2+ influx cannot account for arterial vasoconstriction due to hypoxia during KCl+ contractions. Vascular Vascular responses to hypoxia could have a profound impact on local flow in vivo and could mediate ventilation-perfusion matching in the branchial circulation of fish. (C) 2001Elsevier Science Inc. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/04/20 alle ore 22:57:20