| Abstract: | ![]()
In 3 experiments with male albino Sprague-Dawley rats, injection of polyethylene glycol (PEG) solution (10–30% solution) produced a progressive sequestration of extracellular fluid at the injection site. PEG-treated Ss showed both thirst and sodium appetite. However, water intake began 1–2 hrs after the injections, whereas consumption of NaCl solution did not start until 3–4 hrs later. Then Ss ingested both fluids alternately until plasma volumes were restored, whereupon saline intake became even more prominent and water was consumed due to induced osmoregulatory needs. These 3 phases were seen regardless of the dose of PEG or the concentration of saline. After maintenance on a sodium-deficient diet for 2–4 days or after bilateral adrenalectomy, Ss increased their intake of saline immediately after PEG treatment. Findings suggest that the delayed onset of sodium appetite after PEG treatment that occurred when Ss were maintained on standard sodium-rich chow resulted from the buffer provided by surplus extracellular fluid in those Ss. They further suggest that sodium appetite may be stimulated by a decreased availability of sodium in the brain. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
