Exposure to phthalate plasticizer compromises normal brain function in an adult vertebrate

Area of Science:

• Neuroscience
• Environmental Toxicology
• Ecotoxicology

Background:

• Phthalates are widely used plasticizers with known reproductive and developmental effects.
• Diisononyl phthalate (DINP) is often considered a safer alternative to di-2-ethylhexyl phthalate (DEHP).
• Emerging evidence suggests DEHP may impact the vertebrate blood-brain barrier, with potential consequences for brain health.

Purpose of the Study:

• To investigate the acute effects of DEHP and DINP exposure on neuronal function in adult vertebrates.
• To determine if environmentally relevant concentrations of these phthalates impact fundamental brain functions.

Main Methods:

• In vivo intracellular recordings were performed on the Mauthner neuron in goldfish.
• Goldfish were exposed to environmentally relevant concentrations of DEHP or DINP (10 µg/L or 100 µg/L) for one month.
• Analysis focused on sensory input, excitation-inhibition balance, and neuronal conduction speed.

Main Results:

• Both DEHP and DINP exposure altered sensory input to the Mauthner neuron.
• Phthalate exposure disrupted the balance between neuronal excitation and inhibition.
• Conduction speed of the Mauthner neuron was reduced by 20% following exposure to either phthalate.
• Significant effects were observed even at the lower concentration of 10 µg/L.

Conclusions:

• Acute exposure to DEHP and DINP at environmentally relevant levels negatively impacts crucial brain functions in adult vertebrates.
• The study highlights a previously underestimated sensitivity of vertebrate brain function to phthalate exposure.
• Findings suggest potential risks to neurological health from widespread environmental contamination by these common plasticizers.