Abstract
Monoamine neurotransmitters (MAs), including dopamine (DA) and serotonin (5-HT), regulate brain functions such as behavior, memory, and learning. Neonicotinoids are pesticides that are being used more frequently. Neonicotinoid exposure has been observed to produce neurological symptoms, such as altered spontaneous movements and anxiety-like behaviors, which are suspected to be caused by altered MA levels. However, current neurotoxicity tests are not sufficiently sensitive to make these determinations. In this study, we performed some behavior tests and developed a sensitive and accurate analytical method using liquid chromatography-mass spectrometry (LC-MS/MS) to clarify the effects of neonicotinoid administration on MAs in the brain.We orally administered the neonicotinoid imidacloprid (0, 10, and 50 mg/kg body weight) to C57BL/6NCrSlc mice. In behavior tests, the decrease of activity was observed. The LC-MS/MS quantification of MAs in various brain regions by tetrafluoroborate salt of 2,4-diphenyl-pyranylium (DPP) derivatization, which was newly developed in this study, showed a decrease in some MA levels in the olfactory bulb and the striatum.Thus, in this study, we developed a new method for the sensitive detection of MAs by LC/MS using DPP derivatization. In addition, we showed that this sensitive MA quantification is effective in clarifying the neurotoxicity caused by chemical substances.
Development of a Highly Sensitive and Simultaneous Analytical Method for 20 Elements in Raw and Tap Waters Using DRC-ICP/MS and Removal Characteristics of These Elements in the Process of Water Treatment
