Di (2-ethylhexyl) phthalate modulates cholinergic mini-presynaptic transmission of projection neurons in Drosophila antennal lobe

Di (2-ethylhexyl) phthalate (DEHP) is one of the Phthalic acid esters which are added in polyvinyl chloride (PVC) products. Previous animal studies have showed that exposure to DEHP has a negative effect on the liver, kidneys, lungs, and reproductive system, particularly the developing testes of prenatal and neonatal males, but few can match the dramatic impact on the nervous system. Drosophila melanogaster as a model organism has been widely used in research of the nervous system. In order to examine the modulation of DEHP in excitatory cholinergic transmission, electrophysiological properties of spontaneous activities, spontaneous action potential (sAP), mini excitatory postsynaptic currents (mEPSCs), and calcium currents were measured in projection neurons (PNs) of Drosophila antennal lobe. In this study, DEHP (100 μM) was showed to influence the spontaneous activities of the PNs and DEHP (300 μM) significantly decrease the frequency of sAP. Meanwhile, DEHP (100 and 300 μM) also reduced the frequency and amplitude of mEPSCs. Furthermore, ion channel studies showed DEHP (100 and 300 μM) inhibited the peak current amplitude of calcium channel. These results indicated that the DEHP modulated the cholinergic mini-synaptic transmission of projection neurons in Drosophila antennal lobe, and this modulation might be mediated by inhibiting the calcium channel activities.