title: Osmotic and volaemic effects on drinking rate in elasmobranch fish.
abstract: An increase in drinking rate of two species of marine elasmobranch fish, Scyliorhinus canicula and Triakis scyllia, acclimated to 80 % sea water was observed following the introduction of 100 % sea water to experimental tanks. The drinking response in both species was found to be maximal within 6 h, and a significant increase was sustained for up to 24 h in T. scyllia. Plasma osmolality was significantly increased within 6 h following introduction of 100 % sea water, and this increase was principally due to elevated plasma Na(+) and Cl(-) concentrations. Administration of 2 mol l(-1) mannitol, 75 % sucrose and vehicle (elasmobranch Ringer) did not induce a significant increase or decrease in the drinking rate of S. canicula. However, injection of 20 % NaCl was found to decrease drinking rate significantly in S. canicula 60 min after administration. Controlled haemorrhage of approximately 5.7 % of total blood volume in S. canicula induced a rapid 36-fold increase in drinking over basal levels. The present study demonstrates a physiological dipsogenesis in response to hypovolaemia in marine elasmobranch fish as part of their overall iso/hyperosmoregulatory strategy.
authors.affiliation: School of Biology, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife KY16 8LB, Scotland, UK. wga@st-andrews.ac.uk
authors.forename: W Gary
authors.initials: WG
authors.lastname: Anderson
authors.forename: Y
authors.initials: Y
authors.lastname: Takei
authors.forename: N
authors.initials: N
authors.lastname: Hazon
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis; D001790:Blood Physiological Phenomena / Q000187:drug effects; D004327:Drinking Behavior / Q000187:drug effects / Q000502:physiology*; D018940:Elasmobranchii / Q000502:physiology*; D005260:Female; D006470:Hemorrhage / Q000097:blood / Q000503:physiopathology; D006863:Hydrogen-Ion Concentration; D008297:Male; D009994:Osmolar Concentration; D012623:Seawater; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D013395:Sucrose / Q000494:pharmacology
chemical_list: D012965:Sodium Chloride; D013395:Sucrose