Fluoride has been known as an environmental pollutant. It is of interest to know whether or not neurological effects can be induced in experimental animals by oral exposure to fluoride. Adult male rats were administered fluoride via their drinking water at the concentrations of 0, 50, 100, or 200 ppm for 2 months. Following the treatment period, the body weights of the rats were checked, and their brains, livers, kidneys, and spleens were sampled. The brain samples were dissected into seven regions (cerebrum, cerebellum, medulla oblongata, midbrain, corpus striatum, hypothalamus, and hippocampus). The levels of the catecholamines which were norepinephrine (NE), dopamine (DA), DA metabolites dihydroxyphenylacetic acid (DOPAC) and homovallic acid and those of the indoleamine serotonin (5-hydroxytryptamine) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in each brain region were simultaneously determined by high performance liquid chromatography (HPLC) with an electrochemical detector. The mean body weight in the 200-ppm group was significantly lower than those in the control, 50-ppm, and 100-ppm groups. There were no significant differences among the groups for relative liver, kidney, or spleen weights. The mean values of NE in the medulla of the 100-ppm and 200-ppm groups were significantly lower than those in the control and 50-ppm groups. The mean values of 5-HIAA in the 100-ppm and 200-ppm groups were significantly lower than that in the 50-ppm group. However, they were also significantly lower than that in the control. The mean values of DA in the medulla in the 100-ppm and 200-ppm groups were significantly lower than that in the 50-ppm group and tended to be lower than that in the control. No significant differences were observed in the levels of the neurotransmitters and their metabolites in other brain regions. The mean value of DOPAC/DA ratio in the midbrain in the 50-ppm group was significantly higher than that in the control, 100-ppm and 200-ppm groups. The administration of fluoride at the concentration of 200 ppm in the drinking water for 2 months inhibits the increase in body weight. However, under such experimental conditions, significant alterations in the neurotransmitters and their metabolites were observed in limited regions but were not dose dependent. The neurotoxic effects of fluoride by oral exposure may not be strong.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/28309 must be provided.