Detection of blood volume deficits alters a rats motivational state by stimulating thirst and salt appetite. In consequence, PEG-treated rats with established hypovolemia adaptively drink both water and hypertonic NaCl solution; indeed, they quickly alternate between drinking both fluids and concoct a mixture isotonic to body fluids a concentration that is most effective in repairing plasma volume deficits without perturbing pOsm. However, their plasma volume deficits cannot be restored until ingested fluid is absorbed from the GI tract. The present experiment sought to address the issue of whether ingested water accelerates ingestion, gastric emptying, and small intestinal absorption of 0.30 M NaCl. In fact, ingestion of both water and 0.30 M NaCl did accelerate fluid delivery into the systemic circulation. Moreover, as a consequence of fluid leaving the GI tract more quickly, GI distension signals associated with inhibition of fluid intake are quickly removed, leading to larger fluid intakes. The unique behavior of PEG-treated rats corresponds to restoration of their body fluid deficits, including behavioral, physiological, and hormonal aspects of body fluid homeostasis. Clearly, co-existence of thirst and salt appetite is an adaptive behavioral response to hypovolemia.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-08082007-131950 |
| Date | 19 September 2007 |
| Creators | Bykowski, Michael Ryan |
| Contributors | Edward M. Stricker, Linda Rinaman, Alan Sved |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-08082007-131950/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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