Comparison of the effects of chronic water deprivation and hypertonic saline ingestion on cerebral protein synthesis in rats.

The effects of 3 days water deprivation and 3 days with 2% (w/v) NaCl in drinking water on local rates of methionine incorporation into brain proteins were compared by means of a quantitative autoradiographic method with L-[35S]methionine. The two conditions of chronic dehydration resulted in large increases in the rate of methionine incorporation in the supraoptic (SON), magnocellular paraventricular (mPVN) and arcuate nuclei of the hypothalamus, and in the subfornical organ (SFO). Significant increases of lower amplitude occurred as a result of both treatments in the anteroventral third ventricle area, parvocellular paraventricular nucleus and locus coeruleus. Water deprivation caused larger increases of protein synthesis than hypertonic saline ingestion in the SON, mPVN and SFO. These results indicate that following chronic dehydration, increases in protein synthesis occur mainly in forebrain areas involved in the regulation of water balance, whereas no major changes in protein synthesis occur in brainstem areas involved in the control of blood volume and pressure.