Environmental enrichment reverses cognitive and molecular deficits induced by developmental lead exposure

Ann Neurol. 2003 Jan;53(1):50-6. doi: 10.1002/ana.10399.

Abstract

Long-term deficits in cognitive function are the principal effects of lead (Pb2+) exposure in children and can be modeled in experimental animals. Current therapeutic approaches in the treatment of childhood Pb2+ intoxication are not effective in reversing learning deficits once they have occurred. We report that environmental enrichment reverses long-term deficits in spatial learning produced by developmental Pb2+ exposure in rats. Enhanced learning performance of Pb2+-exposed animals reared in an enriched environment was associated with recovery of deficits in N-methyl-D-aspartate receptor subunit 1 (NR1) mRNA and induction of brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus. The effect of environmental enrichment on NR1 and BDNF gene expression was specific to Pb2+-exposed animals and was present in the absence of changes in the NR2B subunit of the N-methyl-D-aspartate receptor, GluR1, alpha CamKII, or PSD-95 gene expression measured in the same animals. Our findings demonstrate that the learning impairments and NR1 subunit mRNA deficits resulting from developmental Pb2+ exposure are reversible if the animals are provided with an enriched environment even after the exposure has occurred. We propose environmental enrichment as a basis for the treatment of childhood Pb2+ intoxication.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Animals
  • Body Weight
  • Brain-Derived Neurotrophic Factor / genetics
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • Cognition Disorders / physiopathology*
  • Cognition Disorders / therapy*
  • Conditioning, Psychological / physiology
  • Disease Models, Animal
  • Disks Large Homolog 4 Protein
  • Environment*
  • Female
  • Gene Expression
  • Hippocampus / physiology
  • Intracellular Signaling Peptides and Proteins
  • Lead Poisoning, Nervous System / physiopathology*
  • Lead Poisoning, Nervous System / therapy*
  • Membrane Proteins
  • Nerve Tissue Proteins / genetics
  • Rats
  • Rats, Long-Evans
  • Receptors, AMPA / genetics
  • Receptors, N-Methyl-D-Aspartate / genetics
  • Space Perception / physiology

Substances

  • Brain-Derived Neurotrophic Factor
  • Disks Large Homolog 4 Protein
  • Dlg4 protein, rat
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • NR1 NMDA receptor
  • Nerve Tissue Proteins
  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • postsynaptic density proteins
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Calcium-Calmodulin-Dependent Protein Kinases
  • glutamate receptor ionotropic, AMPA 1