, Volume 33, Issue 4, pp 309–328 | Cite as

Excitant and depressant drugs modulate effects of environment on brain weight and cholinesterases

  • Edward L. Bennett
  • Mark R. Rosenzweig
  • Su -Yu Chang Wu
Animal Studies


Certain excitant drugs can enhance the effects of enriched experience on weights of brain sections and on the activities of acetylcholinesterase and cholinesterase in the brain, and certain depressants can lessen the brain weight effects. Most experiments were performed with prepubertal male rats. Some rats were exposed in groups of 12 to an enriched environmental condition (EC), usually for 2 h per day and over a 30-day period; others remained in their individual home cages (HC) throughout. Some received a drug injection and others received a saline injection before the daily EC period; HC controls received similar injections. The drug injections had no significant effects on brain values of HC rats, but they altered effects of EC, probably by influencing the animals' reactions to the environment. Methamphetamine and d-amphetamine enhanced the EC effects; metrazol had small positive effects, and strychnine was without effect. Phenobarbital depressed the brain weight effects but increased the enzymatic effects. Use of Methamphetamine made it possible to find EC effects with short daily periods (30 min) or with a shortened experimental duration (15 days). In experiments with adult rats, meth-amphetamine did not modulate the brain weight effects. The results of this study may bear on the use of stimulants to promote recovery from brain damage.

Key words

Methamphetamine d-Amphetamine Phenobarbital Acetylcholinestersae Brain Weight Enriched Environment Brain Injury 


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  1. Bennett, E. L., Diamond, M. C., Krech, D., Rosenzweig, M. R.: Chemical and anatomical plasticity of brain. Science 146, 610–619 (1964)Google Scholar
  2. Ellman, G. L., Courtney, K. D., Andres, B. N., Jr., Featherstone, R. M.: A new and rapid determination of acetylcholinesterase activity. Biochem. Pharmacol. 7, 88–95 (1961)Google Scholar
  3. Ferchmin, P. A., Eterovic, V. A., Caputto, R.: Studies of brain weight and RNA content after short periods of exposure to environmental complexity. Brain Res. 20, 49–57 (1970)Google Scholar
  4. Florio, V., Longo, V. G.: Electroencephalographic effects of bicuculline. Physiol. Behav. 9, 283–285 (1972)Google Scholar
  5. Geller, E., Yuwiler, A., Zolman, J.: Effects of environmental complexity and training on constituents of brain and liver. J. Neurochem. 12, 949–955 (1965)Google Scholar
  6. Henderson, N. D.: Genetic influences on the behavior of mice can be obscured by laboratory rearing. J. comp. physiol. Psychol. 72, 505–511 (1970)Google Scholar
  7. Kumar, R.: Exploration and latent learning: Differential effects of desamphetamine on components of exploratory behavior in rats. Psychopharmacologia (Berl.) 16, 54–72 (1969)Google Scholar
  8. Levitan, I. B., Mushynski, W. E., Ramirez, G.: Effects of an enriched environment on amino acid incorporation into rat brain sub-cellular fractions in vivo. Brain Res. 41, 498–502 (1972)Google Scholar
  9. Levitan, I. B., Mushynski, W. E., Ramirez, G.: Effects of environmental complexity on amino acid incorporation into rat cortex and hippocampus in vivo. J. Neurochem. 19, 2521–2530 (1972)Google Scholar
  10. Riege, W. H., Morimoto, H.: Effects of chronic stress and differential environments upon brain weights and biogenic amine levels in rats. J. comp. physiol. Psychol. 71, 396–404 (1970)Google Scholar
  11. Robbins, T., Iversen, S. D.: A dissociation of the effects of d-amphetamine on locomotor activity and exploration in rats. Psychopharmacologia (Berl.) 28, 155–164 (1973)Google Scholar
  12. Rosenzweig, M. R., Bennett, E. L.: Effects of differential environments on brain weights and enzyme activities in gerbils, rats, and mice. Devel. Psychobiol. 2, 87–95 (1969)Google Scholar
  13. Rosenzweig, M. R., Bennett, E. L.: Cerebral changes in rats exposed individually to an enriched environment. J. comp. physiol. Psychol. 80, 304–313 (1972)Google Scholar
  14. Rosenzweig, M. R., Bennett, E. L., Diamond, M. C.: Chemical and anatomical plasticity of brain: Replications and extensions, 1970. In: J. Gaito (Ed.): Macromolecules and behavior, 2nd ed., pp. 205–277. New York: Appleton-Century-Crofts 1972Google Scholar
  15. Rosenzweig, M. R., Krech, D., Bennett, E. L., Diamond, M. C.: Effects of environmental complexity and training on brain chemistry and anatomy: A replication and extension. J. comp. physiol. Psychol. 55, 429–437 (1962)Google Scholar
  16. Rosenzweig, M. R., Love, W., Bennett, E. L.: Effects of a few hours a day of enriched experience on brain chemistry and brain weights. Physiol. Behav. 3, 819–825 (1968)Google Scholar
  17. Rosner, B. S.: Brain functions. Ann. Rev. Psychol. 21, 555–594 (1970)Google Scholar
  18. Schwartz, S.: Effect of neonatal cortical lesions and early environmental factors on adult rat behavior. J. comp. physiol. Psychol. 57, 72–77 (1964)Google Scholar
  19. Tower, D. B. (Ed.): Neurochemistry in the Soviet Union. Report of the Neurochemistry Delegation to the USSR, 1969, U.S. Department of Health, Education, and Welfare.Google Scholar
  20. Volkmar, F. R., Greenough, W. T.: Rearing complexity affects branching of dendrites in the visual cortex of the rat. Science 176, 1445–1447 (1972)Google Scholar
  21. Walsh, R. N., Budtz-Olsen, O. E., Penny, J. E., Cummins, R. A.: The effects of environmental complexity on the histology of the rat hippocampus. J. comp. Neurol. 137, 261–266 (1969)Google Scholar
  22. Ward, A. A., Jr., Kennard, M. A.: Effect of cholinergic drugs on recovery of function following lesions of the central nervous system in monkeys. Yale J. Biol. Med. 15, 189–228 (1942)Google Scholar
  23. Watson, C. W., Kennard, M. A.: The effect of anticonvulsant drugs on recovery of function following cerebral cortical lesions. J. Neurophysiol. 8, 221–231 (1945)Google Scholar
  24. West, R. W., Greenough, W. T.: Effect of environmental complexity on cortical synapses of rats: Preliminary results. Behav. Biol. 7, 279–284 (1972)Google Scholar

Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • Edward L. Bennett
    • 1
  • Mark R. Rosenzweig
    • 2
  • Su -Yu Chang Wu
    • 2
  1. 1.Lawrence Berkeley LaboratoryUniversity of CaliforniaBerkeley
  2. 2.Department of PsychologyUniversity of CaliforniaBerkeley

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