Effect of piracetam on cerebral blood flow and somatosensory evoked potential during normotension and hypotensive ischemia in cats.

The effect of piracetam (Nootrop), 200 mg/kg body weight, on cerebral blood flow (CBF) and somatosensory evoked potential (EP) was studied in a control group (9 cats, mean arterial blood pressure (MABP) = 113.1 +/- 12,63 mmHg, CBF = 71.0 +/- 24.16 ml/100 g/min) and in another group of 11 cats, in which CBF was reduced to 52.2 +/- 20.17 ml/100 g/min by hemorrhagic hypotension (MABP = 55.9 +/- 18.95 mmHg). Piracetam did not affect CBF significantly in the normotensive group, but decreased the EP slightly. The decrease of the surface negative (N1) wave of the EP reached a significant level 10 min (9.9 +/- 12.05%) and 30 min (15.6 +/- 13.05%) after piracetam. In contrast, CBF and EP were increased by piracetam in the hypotensive group: CBF was significantly improved 10 min (32.0 +/- 64.74%) and 30 min (28.8 +/- 45.11%), and N1 10 min (23.0 +/- 26.47%) after piracetam, while the enhancement of the surface positive wave (P1) of the EP reached a significant level during the entire observation period of 90 min. The results indicate a beneficial action of piracetam on brain tissue whose function is impaired by deficient blood supply.