Lasting Increases in Neuronal Activity and Serotonergic Receptor Expression Following Gestational Chlorpyrifos...

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Environmental Toxicology

Background:

• Perinatal exposure to chlorpyrifos (CPF) is linked to neurodevelopmental disorders.
• Previous studies show altered synaptic transmission and serotonin receptor binding post-CPF exposure.
• Functional brain alterations remain largely unknown.

Purpose of the Study:

• Investigate if gestational CPF exposure increases spontaneous firing of inhibitory interneurons.
• Determine if CPF exposure alters serotonin receptor expression in the developing brain.

Main Methods:

• Used a rat model for gestational CPF exposure.
• Employed ex vivo electrophysiology to assess neuronal firing in the somatosensory cortex.
• Utilized immunohistochemistry and RNAscope in situ hybridization to analyze neuronal activity and receptor expression.

Main Results:

• CPF-exposed offspring showed increased spontaneous neuronal firing in the somatosensory cortex.
• Fast-spiking parvalbumin (PV) interneurons were identified as a subset of hyperactive neurons.
• Increased expression of the 5-HT1B receptor was observed in PV neurons of male offspring.

Conclusions:

• Gestational CPF exposure may lead to persistent somatosensory cortex hyper-excitation.
• These neurophysiological changes could contribute to CPF-associated behavioral deficits.
• Findings offer insights into mechanisms underlying neurodevelopmental disorders linked to early-life insecticide exposure.