Rates of Formation and Absorption of Cerebrospinal Fluid in Mild Chronic Bovine Hypervitaminosis A

Abstract

Ventriculocisternal perfusion was performed in 12 control calves and 12 calves fed a mildly toxic dose of vitamin A for 12 weeks. The average intraventricular cerebrospinal fluid pressures of these two groups of calves were, respectively, 48 and –14 mm of synthetic cerebrospinal fluid, with corresponding plasma vitamin A concentrations of 35.6 and 96.8 μ/100 ml. Linear regressions of bulk flow, Y, in grams per minute on the imposed ventriculocisternal perfusion pressure (either 0 or +200 mm of the initially determined intraventricular pressure in millimeters of synthetic cerebrospinal fluid), X, were for the control and hypervitaminotic A calves, respectively, Y = −0.002 – 0.00177X and Y = −0.004 – 0.00266X, SD = 0.059 and bulk absorption, Y, in grams per minute, Y = 0.25 + 0.00194X and Y = 0.38 + 0.00239X, SD = 0.07. Rates of formation of cerebrospinal fluid were greater in the hypervitaminotic A calves, 0.37 g/min versus 0.25 g/min in the controls, with a SD of 0.06, and were unaffected by the imposed ventriculocisternal perfusion pressure. The lower cerebrospinal fluid pressure occurring in relatively mild chronic hypervitaminosis A is, therefore, associated with greater bulk absorption of cerebrospinal fluid and decreased resistance to bulk absorption. © 1970, American Dairy Science Association. All rights reserved.