[The nootropic and anxiolytic properties of different doses of piracetam].Eksp Klin Farmakol. 2000 Mar-Apr; 63(2):9-11.EK
The effect of piracetam at various doses on the behavioral and electrophysiological characteristics was studied, including the development of passive and active avoidance conditional reflexes in rats, their behavior in conflict situations, and the transcallosal evoked response (TER) in rabbit brain. In the dose range from 50 to 300 mg/kg, piracetam improved the avoidance performance of both types and produced a dose-dependent increase in the TER amplitude, but did not affect the behavior of rats in conflict situations. As the drug dose was increased to 400-1000 mg/kg, the positive learning influence disappeared (sometimes the effect was even negative) and the TER increase changed to decrease. In contrast, the conflict situation tests revealed pronounced anxiolytic activity of piracetam at elevated doses. Thus, the nootropic and anxiolytic effects of piracetam (and, probably, of the other tranquilizers as well) do not coexist and are significantly shifted relative to one another on the dose scale, being probably realized via different mechanisms.