Prenatal exposure to benzo(a)pyrene impairs later-life cortical neuronal function

Area of Science:

• Neuroscience
• Environmental Health
• Developmental Biology

Background:

• Prenatal exposure to environmental contaminants like benzo(a)pyrene (B(a)P) can negatively impact brain development.
• Glutamate receptor subunit expression is vital for cortical function and development.

Purpose of the Study:

• To investigate the effects of prenatal B(a)P exposure on the developmental expression of glutamatergic receptor subunits in the rat somatosensory cortex.
• To characterize the impact of prenatal B(a)P exposure on cortical evoked responses and neuronal activity.

Main Methods:

• Pregnant Long Evans rats were exposed to low-level B(a)P during gestation.
• Offspring were assessed for B(a)P metabolites, NR2B mRNA expression via RT-PCR, and NMDA receptor-dependent neuronal activity in the barrel cortex.
• Neural activity was recorded following whisker stimulation.

Main Results:

• Prenatal B(a)P exposure did not affect litter size, growth, or brain-body weight ratios.
• A significant 50% reduction in NR2B mRNA expression was observed in B(a)P-exposed offspring.
• NMDA receptor-dependent neuronal activity was reduced by 70% in the barrel cortex of exposed offspring, with deficits most pronounced at shorter latencies (5-20 ms).

Conclusions:

• In utero exposure to B(a)P diminishes NR2B mRNA expression, leading to late-life deficits in cortical neuronal activity.
• Prenatal B(a)P exposure negatively impacts offspring brain function, particularly during critical periods of synaptic development and sensory pathway maturation.