Simultaneous investigation of the cerebral circulation and cortical bioelectrical activity in dogs under the influence of piracetam.

By means of the methods of local cerebral rheoencephalography (REG) and electroencephalography (EEG) the effect of piracetam (1-acetamide-2-pyrrolidone, Pyramem) on cerebral circulation and brain bioelectrical activity was studied in acute experiments on dogs. The following REG parameters were assayed: anacrotic section of the curve and its relative part, amplitude and dicrotic index. The influence of the preparation on the spontaneous EEG was studied by means of surface electrodes, pH, pO2, and pCO2 were determined in blood samples from femoral artery and superior sagittal sinus and arterio-venous differences of O2 (AVD-O2) and CO2 (AVD-CO2) were calculated. The arterial pressure and ECG were followed continuously. The results showed that after piracetam administration (100 mg/kg i.v.) an improvement of the REG parameters is observed: increase of the amplitude and decrease of the values of the relative part and dicrotic index. The changes observed indicated cerebro-vascular resistance decrease and increase of the cerebral blood volume. The AVD-O2 increased and the negative AVD-CO2 decreased. The EEG data indicated an improvement in the functional state of the brain cortex. Suggestions as to mechanism of piracetam effect and the usefulness of the methods were made.