Blockade of the nootropic action of piracetam-like nootropics by adrenalectomy: an effect of dosage?

The present experiments demonstrate that the absence of any memory-improving action of nootropics in adrenalectomized animals cannot be ascribed to an effect of dosage. Doses of 1, 10, 100, 1000 and 3000 mg/kg p.o. of piracetam, oxiracetam, aniracetam or pramiracetam are ineffective in adrenalectomized mice.