Biologists investigate effects of bisphenols on nerve cells

Date:
April 12, 2021
Source:
Universita"t Bayreuth
Summary:
Bisphenols contained in many everyday objects can impair important
brain functions in humans, biologists warn. Their study shows that
even small amounts of the plasticizers bisphenol A and bisphenol
S disrupt the transmission of signals between nerve cells in
the brains of fish. The researchers consider it very likely that
similar interference can also occur in the brains of adult humans.



FULL STORY ==========================================================================
The plasticisers contained in many everyday objects can impair important
brain functions in humans. Biologists from the University of Bayreuth warn
of this danger in an article in Communications Biology. Their study shows
that even small amounts of the plasticisers bisphenol A and bisphenol S
disrupt the transmission of signals between nerve cells in the brains of
fish. The researchers consider it very likely that similar interference
can also occur in the brains of adult humans. They therefore call for
the rapid development of alternative plasticisers that do not pose a
risk to the central nervous system.


========================================================================== Bisphenols are plasticisers that are found in a large number of plastic products worldwide -- for example, in food packaging, plastic tableware, drinking bottles, toys, tooth fillings, and babies' dummies. In recent
years, numerous health risks have already been associated with them,
especially with bisphenol A (BPA). The Bayreuth research team led
by Dr. Peter Machnik at the Animal Physiology research group (led by
Prof. Dr. Stefan Schuster) has now for the first time investigated the
effects of plasticisers on signal transmission between nerve cells in the
adult brain. The study covers not only BPA, but also bisphenol S (BPS),
which is often considered less harmful to health. Their findings: Both plasticisers impair communication between the nerve cells of the brain.

Permanent damage to the nervous system The harmful effects on the
brain mainly affect the delicate balance between different neuronal
functions. While some brain cells transmit signals that trigger a state
of excitation in downstream cells, other brain cells have the function of inhibiting downstream cells. However, the coordination of both excitation
and inhibition is essential for an intact central nervous system.

"It is well known that numerous disorders in the nervous system of
vertebrates are triggered by the fact that excitatory signals and
inhibitory signals are not or only inadequately coordinated. So, it is
all the more alarming that the plasticisers BPA and BPS significantly
impair precisely this coordination," explains Dr. Peter Machnik, lead
author of the study.

"We were surprised how many vital brain functions in fish are affected
by the plasticisers used in numerous industries. This damage, as we were
able to show, does not occur immediately. However, when the brain cells
are exposed to small amounts of BPA or BPS for a month, the damage is unmistakable," says Elisabeth Schirmer, a doctoral student from Bayreuth
and first author of the study. It turns out that the plasticisers
influence the action potential of brain cells.

They alter the chemical and electrical transmission of signals through
the synapses. In addition, they disrupt the circuits that are important
for the perception and processing of acoustic and visual stimuli.

Studies on Mauthner cells in goldfish The discovery of the damage caused
by plasticisers came from detailed studies on live goldfish. The focus
was on the two largest nerve cells in fish brain, the Mauthner cells. They integrate all sensory stimuli, all of which must be processed quickly and
in a precisely coordinated manner when predators approach. In this case,
the Mauthner cells trigger life-saving escape reactions. Due to this
function, which is essential for survival, they have become particularly
robust in the course of evolution. Mauthner cells are able to ward off
damaging influences to a certain extent, or to compensate for damage afterwards. This makes it all the more significant that plasticisers
are able to cause considerable damage to these cells.

Transferability of the results to humans -- Demand for alternative
plasticisers "The findings obtained through studies on fish brains justify
the assessment that BPA and BPS can also seriously damage the brains of
adult humans. Against this background, it is essential that science and industry develop new plasticisers to replace these bisphenols, while
being safe for human health," says Dr. Peter Machnik. Prof. Dr. Stefan
Schuster adds: "The efficiency of the research techniques we used in
our study could, in addition, prove a valuable aid in the development
of alternative plasticisers. They make it possible to quickly and
inexpensively test how a substance under consideration affects brain
cells." The research was funded by the German Research Foundation (DFG)
as part of a Reinhart Koselleck project.

========================================================================== Story Source: Materials provided by Universita"t_Bayreuth. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Elisabeth Schirmer, Stefan Schuster, Peter Machnik. Bisphenols exert
detrimental effects on neuronal signaling in mature vertebrate
brains.

Communications Biology, 2021; 4 (1) DOI: 10.1038/s42003-021-01966-w ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/04/210412114839.htm

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