Effects of Changes in Serum Osmolarity on Bulk Flow of Fluid into Cerebral Ventricles and on Brain Water Content
Overview
Authors
Affiliations
The effects of changes in serum osmolarity on the rate and osmolarity of bulk flow of fluid into the cerebral ventricles and on cortical white and grey matter water content were studied in cats. Bulk flow rates and osmolarities were measured during ventriculocisternal perfusion both before and after intravenous infusion of glucose solutions. Infusions of glucose in concentrations greater than 6% decreased fluid bulk flow rate and its osmolarity. Glucose in concentrations less than 6 percent increased fluid bulk flow rate and decreased its osmolarity. Bulk flow rate and serum osmolarity were found to be linearly related with a coefficient of osmotic flow of minus 0.835 mul/min per mOsm/l. At the extremes of induced serum osmolarities, (290 and 360 mOsm/l) bulk flow rate was either increased by 120 percent or completely inhibited. Effluent osmolarity also increased proportionately to serum osmolarity (0.338 mOsm/l per mOsm/l). When compared to controls, cortical grey and white matter water content increased by 1.9 percent and 2.9 percent, respectively, when the infused glucose concentration was 2.5 percent or less, and decreased by 1.8 percent and 2.9 percent when the concentration was 10 percent or more. The results of these experiments suggest that the increased bulk flow comes from the brain, rather then directly from the blood.
Oernbo E, Steffensen A, Razzaghi Khamesi P, Toft-Bertelsen T, Barbuskaite D, Vilhardt F Fluids Barriers CNS. 2022; 19(1):65.
PMID: 36038945 PMC: 9422132. DOI: 10.1186/s12987-022-00358-4.
Wittbrodt M, Sawka M, Mizelle J, Wheaton L, Millard-Stafford M Physiol Rep. 2018; 6(16):e13805.
PMID: 30136401 PMC: 6105626. DOI: 10.14814/phy2.13805.
Starling forces drive intracranial water exchange during normal and pathological states.
Linninger A, Xu C, Tangen K, Hartung G Croat Med J. 2018; 58(6):384-394.
PMID: 29308830 PMC: 5778682. DOI: 10.3325/cmj.2017.58.384.
New concepts in the pathogenesis of hydrocephalus.
Krishnamurthy S, Li J Transl Pediatr. 2016; 3(3):185-94.
PMID: 26835336 PMC: 4729848. DOI: 10.3978/j.issn.2224-4336.2014.07.02.
A computational model of cerebrospinal fluid production and reabsorption driven by Starling forces.
Buishas J, Gould I, Linninger A Croat Med J. 2014; 55(5):481-97.
PMID: 25358881 PMC: 4228294. DOI: 10.3325/cmj.2014.55.481.