APStracts 5:0092F, 1998.

Cerebrospinal fluid formation and absorption in dehydrated sheep. Chodobski, Adam, Joanna Szmydynger-Chodobska, and Michael J. McKinley. Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria 3052, Australia

APStracts 5:0092F, 1998.

Cerebrospinal fluid (CSF) plays an important role in the brain's adaptive response to acute osmotic disturbances. In the present experiments, the effect of 48-h dehydration on CSF formation and absorption rates was studied in conscious adult sheep. Animals had cannulas chronically implanted into the lateral cerebral ventricles and cisterna magna to enable the ventriculocisternal perfusion. A 48 -h water deprivation altered neither CSF production nor resistance to CSF absorption. However, in the water-depleted sheep intraventricular pressure tended to be lower than that found under control conditions. This likely resulted from decreased extracellular fluid volume and a subsequent drop in central venous pressure occurring in dehydrated animals. In conclusion, our findings provide evidence for the maintenance of CSF production during mild dehydration, which may play a role in the regulation of fluid balance in the brain during chronic hyperosmotic stress.

Received 5 June 1997; accepted in final form 1 May 1998.
APS Manuscript Number F183-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 8 May 1998