EFFECT OF FLUNARIZINE AND METHYLPREDNISOLONE ON FUNCTIONAL RECOVERY AFTER EXPERIMENTAL SPINAL-INJURY

The effect of flunarizine and methylprednisolone on the recovery of so matosensory evoked potentials (SEPs) was evaluated in an experimental model of spinal cord impact injury in anesthetized cats. In addition, the effect of flunarizine on posttraumatic spinal cord blood flow (SCB F) (using the hydrogen clearance technique) and interstitial calcium a nd potassium activity (ion-selective electrodes) was investigated. Aft er the injury (600 g . cm), SEPs disappeared, followed by a spontaneou s recovery to 17% of the preinjury amplitude at the end of the 4 h obs ervation period. Flunarizine treatment (0.1 mg/kg IV, given 5 and 120 min after injury) resulted in a significantly improved recovery of SEP s, reaching 52% of the preinjury amplitude. Methylprednisolone treatme nt (30 mg/kg IV, given 5 min after injury) resulted in a 30% recovery level, significantly better than in untreated animals but significantl y inferior to flunarizine treatment. Combination of both treatments re sulted in a 62% recovery level, significantly better than after methyl prednisolone treatment alone. Flunarizine treatment had no significant effect on the postinjury evolution of SCBF and interstitial potassium activity; it did, however, significantly accelerate the recovery of i nterstitial calcium activity, which sharply decreased immediately afte r injury. It is concluded that intravenous administration of the calci um entry blocker flunarizine improves the functional recovery of the s pinal cord in the acute phase after experimental spinal impact injury. The observed improvement is not achieved by an effect on local blood flow but is possibly related to an inhibitory effect of the drug on ce llular calcium entry.