Part I.: Effect of Hyperextension-Hyperflexion (Whiplash) on the Function of the Blood-Brain Barrier of Rhesus Monkeys

AbstractFifteen rhesus monkeys were placed in a cart and subjected to a sudden acceleration to administer a whiplash. The intensity of the acceleration of the head was determined either with a high-speed movie or from accelerometers mounted on the skull. The cart was maximally accelerated to a peak acceleration of 35 g's at 30 ms after onset of the impact, and the maximal angular acceleration was 40 × 103 rad/s2 at 50 ms. The animals did not apparently lose consciousness. The permeability of the blood-brain barrier (BBB) was assessed, prior to and 1 hour after the whiplash trauma using intravenously administered radioactive pertechnetate (99mTc). The ratio of radioactivity in the cerebrospinal fluid to that in the blood 1 hour after administration served as a measure of the blood-brain barrier permeability. Prior to the whiplash trauma this ratio was 4.85 × 10-3, and after the trauma it had increased to 28.44 × 10-3. This acute change in barrier function may contribute to the alterations in function of th...