Perinatal Exposure to Metal Mixtures Disrupts Neuronal Function and Behavior

Area of Science:

• Neuroscience
• Environmental Health
• Developmental Toxicology

Background:

• Environmental heavy metal exposure, including lead (Pb), arsenic (As), hexavalent chromium [Cr(VI)], and cadmium (Cd) (PACC), is associated with neurodevelopmental disorders.
• These metals frequently co-occur, yet their combined impact on brain development is not well understood.

Purpose of the Study:

• To investigate the hypothesis that perinatal exposure to a mixture of environmentally relevant levels of Pb, As, Cd, and Cr(VI) induces developmental defects in cognition, behavior, and neuronal function.

Main Methods:

• Female mice were exposed to single metals or the PACC mixture from preconception through weaning.
• Cognitive and behavioral assessments included open field, novel object recognition, Y-maze, and elevated plus maze tests.
• Whole-cell patch-clamp recordings were performed on medial prefrontal cortex (mPFC) and hippocampal CA1 neurons.

Main Results:

• Perinatal PACC mixture exposure increased anxiety-like behavior and impaired short-term memory.
• Locomotion and working memory were not significantly affected.
• Pyramidal neurons in the mPFC and hippocampal CA1 showed increased intrinsic excitability, with elevated spontaneous excitatory postsynaptic currents in mPFC neurons.

Conclusions:

• Perinatal exposure to the PACC metal mixture disrupts neuronal function and behavior in juvenile mice, potentially leading to long-term neurodevelopmental issues.
• Findings highlight the cognitive and behavioral consequences of combined heavy metal exposure.
• Further research is needed to elucidate the mechanisms underlying heavy metal-induced disruption of neuronal development.