, Volume 56, Issue 3, pp 249–253 | Cite as

PRL-8-53: Enhanced learning and subsequent retention in humans as a result of low oral doses of new psychotropic agent

  • Nikolaus R. Hansl
  • Beverley T. Mead


The effect of 3-(2-benzylmethylaminoethyl) benzoic acid methyl ester hydrochloride (PRL-8-53) on learning and on retention of verbal information in human subjects was investigated. Using the serial anticipation method under double-blind conditions it was found that PRL-8-53 causes slight improvement of acquisition. Retention of verbal information was found improved to a statistically significant degree (most P values better than 0.01, some better than 0.001). No significant changes were found for either visual reaction time or motor control after drug when compared with placebo values.

Key words

Learning Memory Benzoic acid derivatives Phenethylamines 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Boshes, B., Arbit, J.: A controlled study of the effects of l-dopa upon selected cognitive and behavioral functions. Trans. Am. Neurol. Assoc. 95, 59–63 (1970)Google Scholar
  2. Deutsch, J. A., Lutzky, H.: Memory enhancement by anti-cholinesterase as a function of initial learning. Nature 213, 742 (1967)Google Scholar
  3. Erickson, C. K.: Studies on the mechanism of avoidance facilitation by nicotine. Psychopharmacologia (Berl.) 22, 357–368 (1971)Google Scholar
  4. Glassman, E.: The biochemistry of learning: an evaluation of the role of RNA and protein. Annu. Rev. Biochem. 38, 605–646 (1969)Google Scholar
  5. Hansl, N.: Synthesis and biological activity of m-(2-aminoalkyl)-benzoic acid derivatives. Abst. Am. Chem. Soc. Med. 57 (1973)Google Scholar
  6. Hansl, N.: A novel spasmolytic and CNS active agent: 3-(2-benzylmethyl amino ethyl) benzoic acid methyl ester hydrochloride. Experientia 30, 271 (1974a)Google Scholar
  7. Hansl, N.: Process for hydrolyzing 3-trifluoromethyl phenethylamines. U.S. Patent 3,792,048 (1974b)Google Scholar
  8. Hansl, N.: Pharmacologic and toxicologic parameters of a novel psychotropic agent, 3-(2-benzylmethylamino ethyl) benzoic acid methyl ester hydrochloride. Proc. Nebr. Acad. Sciences 9, (1974c)Google Scholar
  9. Hoffmann-La Roche & Cie: Meta-(2-Substituted aminoethyl) benzoic acid derivatives — Spasmolytics, psychotherapeutic and cholinergic agents. Belg. Patent 788, 850 (1973)Google Scholar
  10. Krivanek, J. A., McGaugh, J. L.: Facilitating effects of pre- and post-trial amphetamine administration on discrimination learning in mice. Agents and Action 1, 34–41 (1969)Google Scholar
  11. McGaugh, J. L., Petrinovich, L. F.: Effects of drugs on learning and memory. International review of neurobiology, C. C. Pfeiffer, ed., vol. 8, pp. 139–196. New York: Academic Press 1965Google Scholar
  12. Merlo, A. B., Izquierdo, J. A.: Effect of post-trial injection of beta adrenergic blocking agents on a conditioned reflex in rats. Psychopharmacologia (Berl.) 22, 181–186 (1971)Google Scholar
  13. Ott, T., Matthies, H.: Some effects of RNA precursors on development and maintenance of long-term memory: hippocampal and cortical pre- and post-training application of RNA precursors. Psychopharmacologia (Berl.) 28, 195–204 (1973)Google Scholar
  14. Rech, R. H.: Effects of cholinergic drugs on poor performance of rats in a shuttle-box. Psychopharmacologia (Berl.) 12, 371–383 (1968)Google Scholar
  15. Robichaud, R. C., Sledge, K. L., Hefner, M. A., Goldberg, M. E.: Propranolol and chlordiazepoxide on experimentally induced conflict and shuttle box performance in rodents. Psychopharmacologia (Berl.) 32, 157–160 (1973)Google Scholar
  16. Schlesinger, K., Schreiber, R. A., Pryor, G. T.: Effects of p-chlorophenylalanine on conditioned avoidance learning. Psychon. Sci. 11, 225–226 (1968)Google Scholar
  17. Smith, R. G.: Magnesium pemoline: lack of facilitation in human learning, memory and performance tests. Science 155, 603–605 (1967)Google Scholar
  18. Tenen, S. S.: The effects of p-chlorophenylalanine, a serotonin depletor, on avoidance acquisition, pain sensitivity and related behavior in the rat. Psychopharmacologia (Berl.) 10, 204–219 (1967)Google Scholar
  19. Wolthuis, O. L.: Experiments with UCB 6215. A drug which enhances acquisition in rats: it's effects compared with those of methamphetamine. European Journal of Pharmacology 16, 283–297 (1971)Google Scholar

Copyright information

© Springer-Verlag 1978

Authors and Affiliations

  • Nikolaus R. Hansl
    • 1
  • Beverley T. Mead
    • 1
  1. 1.Department of Medicinal Chemistry and Department of PsychiatryCreighton UniversityOmahaUSA

Personalised recommendations