Modifications of cAMP in plasma and CSF after experimental brain injury

A dynamic head injury produced by an unconstrained head impact was induced in 30 dogs, out of a total of 45; 15 constituted the control group. Where the energy absorbed by the dog's head is of 59,95 Joules primary brain damage is produced. If the energy absorbed is of 340.31 Joules a severe brain swelling with increase in ICP takes place, leading to the animal's death within 48-96 hours. In the group of animals with a primary brain damage there was no significant change in I.C.P. However, the concentration of cAMP in CSF rose significantly, and this rise continued for 48 hours after impact. In the group of animals with severe secondary brain damage ICP rose significantly from the first post-injury control onwards. The concentration of cAMP in CSF increases significantly after the trauma, but reaches sub-normal levels 48 hours after impact. The plasma concentration of cAMP, on the other hand, is not significantly altered in any of the three groups. The modifications of cAMP in CSF could, in our opinion constitute a good guide for the assessment of the degree of brain damage.