Bisphenol A or BPA is a widely used chemical in the manufacture of plastic containers, inner coatings of cans and thermal paper. Spanish researchers have published a study in Scientific Reports that reveals how this compound increases the sensation of pain in mice. It is the first time that an investigation describes in an animal model how BPA can increase the sensation of pain by modifying the behavior of certain neurons.
To reach this conclusion, experts treated mice with small amounts of BPA, such as those normally found in human blood. The results showed that nociceptor neurons, responsible for transmitting painful sensations, are overexcited when they are in direct contact with BPA and remain more active.
After eight days of treatment with BPA, the mice underwent a temperature test showing greater sensitivity to thermal pain than mice not treated with BPA. After checking this effect, the researchers extracted from the animals the neurons that transmit the painful thermal stimuli to determine the mechanism by which the compound activates all this pain sensation.
“If the neurons responsible for transmitting pain are sensitive to bisphenol A, humans may be more likely to suffer from certain neurological diseases such as sensitivity to thermal pain,” says Sergi Soriano, a University of Alicante (UA) researcher.
In this sense, Soriano points out the possible relationship of BPA with erythromelalgia, a genetic mutation that is characterized by a high sensitivity to pain in the hands, and which is seen in people who work in direct contact with the thermal paper used in shopping tickets.
Precautionary principle for BPA
This work describes not only the effect of BPA on nociceptor neurons, but also reveals the mechanism of action through the alpha estrogen receptor and its interaction with the ion channels responsible for the excitability of sensory neurons.
“If we know the mechanism of action of BPA, we can foresee what other substances of similar structure could produce this effect, as well as identify new endocrine disruptors and design molecules that reduce the action of bisphenol A,” says Soriano.
BPA exposure has been associated with several hormone-related diseases, including obesity and diabetes, female and male reproductive disorders, hormone-sensitive cancers, thyroid hormone level mismatches, and changes in the nervous system, in this case of nociceptor neurons.
Until this substance is banned, as has already happened in some countries, the authors recommend the precautionary principle: use non-plastic containers and opt for ceramics and glass . “It is important to avoid containers marked with the number 3 and 7 within a triangle since they are the ones that contain the greatest amount of BPA,” they add. On the other hand, they warn, the problem increases with exposure to heat since the substance migrates to the food, so they emphasize not heating food packaged in plastic containers.