The effect of intracerebroventricular hypertonic infusion on sodium appetite in rats after peritoneal dialysis.
Sixty minute peritoneal dialysis (PD) against isotonic glucose decreased sodium concentration [Na+] in serum and cerebrospinal fluid (CSF) to 14% and 7% of their initial values, respectively. About 3 to 4 hours after PD, [Na+] began to increase slowly, reaching the initial level 24 hr afterwards. Central restoration of Na+ was made by infusing isotonic or hypertonic fluid into the 3rd brain ventricle (3BV) of rats at different times after dialysis. Continuous infusion (1 microliter/hr) of artCSF, 150 mM Na+, from -1 to 24 hr after PD decreased sodium intake as compared with uninfused control or control receiving Na+-free infusate or distilled water. Hypertonic central sodium infusions (1 microliter/hr) administered from -1 to 8 hr after PD, did not modify sodium intake; however an infusion made from 8 to 24 hr or from 16 to 24 hr post-dialysis decreased sodium intake by 38% and 67%, respectively. The volumes of sodium ingested were compared with those of the same animal infused with CSF 150 mM Na+. The results suggest that the fall in CSF [Na+] after sodium depletion by itself does not seem to be a critical factor in the onset of specific sodium appetite.
D000818:Animals; D001066:Appetite; D002555:Cerebrospinal Fluid / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D011188:Potassium / Q000134:cerebrospinal fluid; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012964:Sodium / Q000097:blood / Q000134:cerebrospinal fluid; D014882:Water-Electrolyte Balance
D012462:Saline Solution, Hypertonic; D012964:Sodium; D011188:Potassium