Effects of emerging contaminants on neurotransmission and biotransformation in marine organisms — An in vitro approach

•Ionic gold displayed toxic effects whereas the nanoparticle form did not.•Glutathione -transferases were more sensitive to inhibition than acetylcholinesterase.•Low concentrations of AuNPs were able to interfere with the effects of human pharmaceuticals.

The effects of gold (ionic form and nanoparticles — AuNPs) and pharmaceuticals (carbamazepine and fluoxetine) on enzymes involved in neurotransmission (acetylcholinesterase — AChE) and biotransformation (glutathione S-transferases — GST) were assessed by their incubation with Mytilus galloprovincialis' hemolymph and subcellular fraction of gills, respectively. AuNPs did not alter enzymatic activities unlike ionic gold that inhibited AChE and GST activities at 2.5 and 0.42 mg·L− 1, respectively. Carbamazepine inhibited AChE activity at 500 mg·L− 1 and fluoxetine at 1000 mg·L− 1. GST was inhibited by carbamazepine at 250 mg·L− 1 and by fluoxetine at 125 mg·L− 1. Increased AChE activity was found in simultaneous exposures to fluoxetine and bovine serum albumin coated AuNPs (BSA-AuNPs). Concerning GST, in the simultaneous exposures, AuNPs revealed protective effects against carbamazepine (citrate and polyvinylpyrrolidone coated) and fluoxetine (citrate and BSA coated) induced inhibition. However, BSA-AuNPs increased the inhibition caused by carbamazepine. AuNPs demonstrated ability to interfere with other chemicals toxicity justifying further studies.