Plasticizers are ingredients essential to producing many everyday plastic objects and are responsible for giving plastic its elastic properties. One plasticizer which has received recent attention is bisphenol A (BPA), a compound found in a wide variety of household objects, from baby products to plastic water bottles. Of late, BPA has been associated with reproductive and developmental health issues, posing a particular concern to us and our environment.
Bisphenol S (BPS) is one of many compounds which has been pushed as a safer alternative to BPA in plastic products. However, few studies have examined the safety of this bisphenol compound or its predecessor on the mature brain. As evidence now emerges against the safety of the substitute BPS, researchers at the University of Bayreuth decided to take a closer at the effects that bisphenols may have on the mature vertebrae brain.
Researchers examined the effect of bisphenols on the activity of the Mauthner neuron in goldfish. The Mauthner neuron processes information from all sensory systems during a sudden escape from a predator, and as such, serves as a good model of neuronal function. Drawing from their sample of 98 fish, experimental groups were set up exposing the fish to differing concentrations of BPA and BPS, as well as a control group exposed only to a DMSO solution.
After a month of exposing the fish to their respective compound, researchers noted an alarming finding: fish exposed to either high or low levels of BPA or BPS generated significantly weaker action potentials. Additionally, exposure to BPA increased the incidence of neuronal backfiring, essentially causing interference which slowed down action potentials. Even auditory and visual processing was impacted by exposure to either BPA or BPS.
These in vivo findings demonstrate that exposure to bisphenols does not only impact the developing brain, as previously thought. At concentrations found in our environment (10 µg L−1), bisphenols were observed to negatively impact neuronal function in the developed brain of goldfish. While future studies are needed to confirm these findings in other organisms, this represents the first study that points to bisphenols impairing essential functions of neurons in the adult central nervous system. Furthermore, it contributes to the growing body of evidence that suggests that bisphenol substitutes to BPA, such as BPS, cannot be considered entirely safe.
The issue of harmful plasticizers in our everyday objects should be revisited, in order to preserve both the physiological health of our brains and bodies and the environmental health of our planet.
Original Source: Schirmer E, Schuster S, Machnik P. Bisphenols exert detrimental effects on neuronal signaling in mature vertebrate brains. Commun Biol. 2021;4(1):465. Published 2021 Apr 12. doi:10.1038/s42003-021-01966-w
Figure 1a: Schirmer E, Schuster S, Machnik P. Bisphenols exert detrimental effects on neuronal signaling in mature vertebrate brains. Commun Biol. 2021;4(1):465. Published 2021 Apr 12. doi:10.1038/s42003-021-01966-w
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