QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online March 2, 2006
Journal of Experimental Biology 209, 1052-1057 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02121

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hartzler, L. K. Articles by Hicks, J. W. Search for Related Content PubMed PubMed Citation Articles by Hartzler, L. K. Articles by Hicks, J. W. Social Bookmarking                         What's this?

Metabolic and blood gas dependence on digestive state in the Savannah monitor lizard Varanus exanthematicus: an assessment of the alkaline tide

L. K. Hartzler^*, S. L. Munns, A. F. Bennett and J. W. Hicks

Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92697-2525, USA

^* Author for correspondence at present address: Wright State University, Neuroscience, Cell Biology, and Physiology, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA (e-mail: lynn.hartzler{at}wright.edu)

Accepted 24 January 2006

A large alkaline tide (up to 20 mmol l^–1 increase in bicarbonate concentration [HCO₃^–] with an accompanied increase in blood pH) has previously been reported for some carnivorous reptiles within 24 h after ingesting a large meal. This phenomenon has been attributed to the secretion of large amounts of H⁺ ions into the stomach, which is required for digestion of large prey items. To test the generality of this phenomenon in carnivorous reptiles, this study quantified the metabolic and acid–base status of the Savannah monitor lizard, Varanus exanthematicus, during digestion at 35°C. Following a meal of approximately 10% of body mass, _O2 and _CO2 were measured continuously and arterial pH, blood gases and strong ions were measured every 8 h for 5 days. During peak digestion (24 h post feeding), _O2 and _CO2 increased to approximately threefold fasting values (_O2, 0.95–2.57 ml min^–1 kg^–1; _CO2 0.53–1.63 ml min^–1 kg^–1) while respiratory exchange ratio (R) remained constant (0.62–0.73). During digestion, arterial P_CO2 increased (from 4.6 kPa to 5.8 kPa), and [HCO₃^–] also increased (from 24.1 mmol l^–1 to 40.3 mmol l^–1). In contrast to early studies on crocodilians, arterial pH in V. exanthematicus remained relatively stable during digestion (7.43–7.56). Strong ions contributed little to the acid–base compensation during the alkalosis. Collectively the data indicate that the metabolic alkalosis associated with H⁺ secretion (as indicated by increased plasma bicarbonate) is partially compensated by a respiratory acidosis.

Key words: Varanus exanthematicus, feeding, specific dynamic action, arterial blood gases, alkaline tide, acid–base balance, metabolic rate, pH

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				C. A. Cooper and R. W. Wilson Post-prandial alkaline tide in freshwater rainbow trout: effects of meal anticipation on recovery from acid-base and ion regulatory disturbances J. Exp. Biol., August 1, 2008; 211(15): 2542 - 2550. [Abstract] [Full Text] [PDF]