Pierre Laurent

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Exposure of adult brown bullheads Ictalurus nebulosus (120–450 g) to environmental hypercapnia (2% carbon dioxide in air) and subsequent recovery caused transient changes in whole body net sodium flux (J net Na+ ) and net chloride flux (J net Cl- ) resulting largely from changes in whole body sodium influx (J in Na+ ) and chloride influx (J in Cl- ).(More)
Fundulus heteroclitus (killifish) is a model organism for ionoregulatory studies, particularly because of its opercular epithelium, although the gills are the major sites of ion exchange. Whereas Na+ and Cl− are excreted through the gills in seawater (SW), the killifish is unusual in taking up only Na+ and not Cl− at the gills in freshwater (FW). We(More)
In this short review of fish gill morphology we cover some basic gross anatomy as well as in some more detail the microscopic anatomy of the branchial epithelia from representatives of the major extant groups of fishes (Agnathans, Elasmobranchs, and Teleosts). The agnathan hagfishes have primitive gill pouches, while the lampreys have arch-like gills(More)
Much of the early research elucidating the general mechanisms of euryhalinity was performed on the common killifish. More recently, its opercular epithelium with abundant mitochondria-rich cells has proven to be a powerful model for analyzing the mechanisms of active NaCl transport under Ussing conditions in vitro (i.e., with isotonic saline on both(More)
CHRIS M. WOOD1, HAROLD L. BERGMAN2, PIERRE LAURENT3, J. N. MAINA4, ANNIE NARAHARA2 AND PATRICK J. WALSH5 1Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1, 2Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA, 3Laboratoire de Morphologie Fonctionnelle et Ultrastructurale des Adaptations, Centre(More)
The Magadi tilapia (Alcolapia grahami, formerly Oreochromis alcalicus grahami) is a remarkable example of teleost life in an extreme environment. Typical conditions include water pH=10, titration alkalinity>300 mM, osmolality=525 mOsm, temperatures ranging from 23 degrees to 42 degrees C, and O(2) levels fluctuating diurnally between extreme hyperoxia and(More)
Opsanus beta expresses a full complement of ornithine-urea cycle (OUC) enzymes and is facultatively ureotelic, reducing ammonia-N excretion and maintaining urea-N excretion under conditions of crowding/confinement. The switch to ureotelism is keyed by a modest rise in cortisol associated with a substantial increase in cytosolic glutamine synthetase for(More)
The aim of this work was to determine the kinetics of the dramatic development of the gill chloride cells (CCs) during adaptation of the salmonid Oncorhynchus mykiss to an ion-poor environment. To monitor cell division, the incorporation in the mitotic cell DNA of bromo-deoxyuridine (BrdUrd) was visualized with a monoclonal antibody. The density of labelled(More)
PURPOSE In the holangiotic retina, little is known about the connections between and the circulation within microvessel layers. The goal of the present study was to explore the three-dimensional arrangement and hemodynamics of mouse retinal microvessels. METHODS Confocal microscopy was performed on fluorescein dextran-filled retinal flatmounts. Capillary(More)