Silver exposure in developing zebrafish produces persistent synaptic and behavioral changes.

Area of Science:

• Environmental toxicology
• Neuroscience
• Developmental biology

Background:

• Increasing environmental silver exposure from silver nanoparticles (AgNPs).
• Silver ions (Ag+) released from AgNPs are suspected developmental neurotoxicants.
• Need to understand long-term neurochemical and behavioral impacts of embryonic Ag+ exposure.

Purpose of the Study:

• To evaluate the long-term neurochemical and behavioral effects of embryonic silver ion (Ag+) exposure in zebrafish.
• To determine if Ag+ exposure at non-morphologically affecting concentrations causes neurotoxicity.
• To assess the persistence of neurochemical and behavioral changes into adulthood.

Main Methods:

• Zebrafish embryos were exposed to 0.03, 0.1, or 0.3 microM Ag+ for five days post-fertilization.
• Neurochemical analysis of dopamine and serotonin turnover in adult zebrafish brains.
• Behavioral assessment using a three-chamber test to evaluate learning and swimming ability.

Main Results:

• Ag+ exposure led to increased dopamine and serotonin turnover in adult zebrafish brains.
• No significant changes were observed in basal neurotransmitter levels.
• Ag+-exposed fish demonstrated faster acquisition of avoidance behavior.
• No alterations in response latency or overall swimming ability were detected.

Conclusions:

• Silver ions (Ag+) act as developmental neurotoxicants, inducing persistent neurochemical and behavioral effects.
• Low-level embryonic Ag+ exposure can result in long-term neurobehavioral alterations.
• Findings reinforce health concerns regarding Ag+ release from environmental silver nanoparticles.