Abstract
This study investigated the effects of paclobutrazol and profenofos on six neurotransmitters and their metabolites involving in cholinergic and non-cholinergic neurotransmission systems in mouse. The results revealed that profenofos decreased the levels of 5-hydroxyindole-3-acetic acid (5-HIAA) and normetanephrine (MNE), and increased the level of dopamine (DA) in the mice after four weeks of exposure. The turnovers of serotonergic neurotransmission system (5-HIAA/5-HT) and noradrenergic neurotransmission system (MNE/NE) showed a decline under exposure of profenofos. Exposure to paclobutrazol resulted in decreases of 5-HIAA and MNE in both sexes of mice, and of 5-HT and ACh in the females. Similar to profenofos, the turnovers of serotonergic neurotransmission system and noradrenergic neurotransmission system decreased in the mice exposed to paclobutrazol. The integrated biomarker response (IBR) was introduced to comprehensively evaluate the neurotoxic effects of the two pesticides through integration of the responses of neurotransmitters. The results of IBR indicated that the overall effect of neurotransmitters increased at the beginning of exposure and then decreased in the end. It was also found that the order of neurotoxic effect for the two pesticides is as: paclobutrazol > profenofos referred to their LD50. Furthermore, the effects on neurotransmitters are higher in the males.