Comment by mobilejdral

Depends on the microplastics, but many act as endocrine disruptors that "mimic" estrogen, tricking the body into over-activating ERa and upregulates the PEMT gene and the higher acetylcholine. It could also be that the microplastics can physically bind to or chemically inhibit acetylcholinesterase and that is the reason for the higher acetylcholine. Depending on the cause this is only a short term good thing, but could be downregulating genes.