Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Environmental enrichment reverses learning impairments caused by lead poisoning

27.11.2002


Environmental enrichment that stimulates brain activity can reverse the long-term learning deficits caused by lead poisoning, according to a study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health. It has long been known that lead poisoning in children affects their cognitive and behavioral development. Despite significant efforts to reduce lead contamination in homes, childhood lead poisoning remains a major public health problem with an estimated 34 million housing units in the United States containing lead paint. The Hopkins study is the first to demonstrate that the long-term deficits in cognitive function caused by lead can be reversed and offers a basis for the treatment of childhood lead intoxication. The findings appear in the online edition of the Annals of Neurology.



“Lead exposure during development causes long-lasting deficits in learning in experimental animals, but our study shows for the first time that these cognitive deficits are reversible,” said lead author Tomás R. Guilarte, PhD, professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health. “This study is particularly important for two reasons. First, it was not known until now whether the effects of lead on cognitive function were reversible. Secondly, the environmental enrichment that reversed the learning deficits was administered after the animals were exposed to lead. Environmental enrichment could be a promising therapy for treating millions of children suffering from the effects of lead poisoning,” added Dr. Guilarte.

For their study, Dr. Guilarte, graduate student Christopher Toscano, research technologist Jennifer McGlothan, and research associate Shelley Weaver observed groups of lead–treated or non-treated (control) rats that were raised in an enriched environment. Enrichment cages were multi-level, containing toys, a running wheel, a hammock, platforms, tunnels, and housed multiple animals. Littermates to these rats were raised in standard-sized laboratory cages that the researchers designated as “isolated environment.” To measure the learning ability of rats in the various treatment groups, the researchers trained each rat to find a submerged, invisible platform in a pool of water, called the water maze. Each day of training, they timed how long each rat took to find the platform. They observed that both the lead-exposed and control rats living in the enriched environment learned to find the platform in 20 seconds or less within the four-day training period. The isolated control rats took longer to find the platform, while lead-exposed isolated rats took the longest and nearly 50 percent of them failed to learn the test by the last day of training.
Along with the enhanced learning performance of lead-exposed rats reared in an enriched environment, the researchers found a recovery in the levels of the NR1 subunit of the N-methyl-D-aspartate receptor (NMDAR) in the hippocampus. The NR1 subunit is obligatory for functional NMDAR and these researchers have previously shown that lead targets the NMDAR. The hippocampus is a brain region important for learning and memory and previous research has determined that the NR1 subunit is essential for learning performance in the water maze.



“We all recognize that children that are intellectually stimulated have a greater capacity to learn. Unfortunately, often times the same children that are exposed to lead, also live in impoverished and neglected homes. It seems that based on our study, many lead-exposed children would benefit from this type of therapeutic approach,” said Dr. Guilarte.

“Environmental Enrichment Reverses Cognitive and Molecular Deficits Induced by Developmental Lead Exposure” was written by Tomás R. Guilarte, PhD, Christopher D. Toscano, MS, Jennifer L. McGlotham, MS, and Shelly A. Weaver, PhD. It is published in the December 2002 edition of the Annals of Neurology.

The research was supported by the National Institute of Environmental Health Sciences.

Public Affairs Media Contacts for the Johns Hopkins Bloomberg School of Public Health:Tim Parsons or Kenna Brigham @ 410-955-6878 or paffairs@jhsph.edu.

Tim Parsons | EurekAlert!
Further information:
http://www.jhsph.edu/Press_Room/Press_Releases/environmental_enrichment.html
http://www.niehs.nih.gov/

More articles from Health and Medicine:

nachricht 'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers
16.02.2018 | National University of Science and Technology MISIS

nachricht New process allows tailor-made malaria research
16.02.2018 | Eberhard Karls Universität Tübingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>