Effect of manganese on biogenic amine metabolism in regions of the rat brain

Iron-Responsive Olfactory Uptake of Manganese Improves Motor Function Deficits Associated with Iron Deficiency

“…Under our study conditions, DAT levels were the same in control and iron-deficient rats, but protein levels were reduced by olfactory manganese exposure in both groups. Similar effects of manganese exposure have been reported in studies of chronic administration by diet [29] or injection [30]. Our study indicates olfactory administration of manganese can also down-regulate DAT, possibly in a more acute manner.…”

“…While some investigations have shown that tissue dopamine levels are altered by iron deficiency, differences in age, circadian cycle, extent of iron depletion, and duration of low iron status between various study groups have led to inconsistent results [5], [7], [10], [11], [28]. Likewise, chronic manganese exposure to the brain across the blood-brain-barrier is thought to diminish dopamine levels [29]–[31], but the olfactory exposure used in our study did not appear to perturb dopamine content, possibly because metal accumulation was lower, manganese deposition was regionally different, and/or the duration of manganese exposure (1–3 weeks) was less than previously studied [29]–[31]. We also studied changes in release and turnover of extracellular dopamine by microdialysis.…”

Iron-Responsive Olfactory Uptake of Manganese Improves Motor Function Deficits Associated with Iron Deficiency

“…Under our study conditions, DAT levels were the same in control and iron-deficient rats, but protein levels were reduced by olfactory manganese exposure in both groups. Similar effects of manganese exposure have been reported in studies of chronic administration by diet [29] or injection [30]. Our study indicates olfactory administration of manganese can also down-regulate DAT, possibly in a more acute manner.…”

“…While some investigations have shown that tissue dopamine levels are altered by iron deficiency, differences in age, circadian cycle, extent of iron depletion, and duration of low iron status between various study groups have led to inconsistent results [5], [7], [10], [11], [28]. Likewise, chronic manganese exposure to the brain across the blood-brain-barrier is thought to diminish dopamine levels [29]–[31], but the olfactory exposure used in our study did not appear to perturb dopamine content, possibly because metal accumulation was lower, manganese deposition was regionally different, and/or the duration of manganese exposure (1–3 weeks) was less than previously studied [29]–[31]. We also studied changes in release and turnover of extracellular dopamine by microdialysis.…”

Behavioral effects of subchronic inorganic manganese exposure in rats

“…In our experiments, a decrease in the spontaneous horizontal and local activity developed after 10 weeks of MnCl 2 exposure, indicating that both serotoninergic and dopaminergic control was probably affected by Mn [Subhash and Padmashree, 1991]. Mn-induced lesion of the nuclei in the hypothalamic lateral area could have contributed to body weight loss and altered motility [Dorman et al, 2000], observed simultaneously from the 6th treatment week to the 1st posttreatment week.…”

Brain Accumulation and Toxicity of Mn(II) and Mn(III) Exposures

“…In summary, the cumulative dose range of manganese used here (30-90 mg Mn/kg body weight) is at the lower range of exposures used in studies reporting adverse effects in rodents (Bonilla and Prasad, 1984;Chandra and Shukla, 1981;Eriksson et al, 1987;Gwiazda et al, 2002;Subhash and Padmashree, 1991). Exposures to Mn(III) produced higher blood and brain manganese concentrations than equimolar exposures to Mn(II), though there were no measurable differences in the manganese accumulation across the four brain regions examined here.…”

Iron-Responsive Olfactory Uptake of Manganese Improves Motor Function Deficits Associated with Iron Deficiency

“…Under our study conditions, DAT levels were the same in control and iron-deficient rats, but protein levels were reduced by olfactory manganese exposure in both groups. Similar effects of manganese exposure have been reported in studies of chronic administration by diet [29] or injection [30]. Our study indicates olfactory administration of manganese can also down-regulate DAT, possibly in a more acute manner.…”

“…While some investigations have shown that tissue dopamine levels are altered by iron deficiency, differences in age, circadian cycle, extent of iron depletion, and duration of low iron status between various study groups have led to inconsistent results [5], [7], [10], [11], [28]. Likewise, chronic manganese exposure to the brain across the blood-brain-barrier is thought to diminish dopamine levels [29]–[31], but the olfactory exposure used in our study did not appear to perturb dopamine content, possibly because metal accumulation was lower, manganese deposition was regionally different, and/or the duration of manganese exposure (1–3 weeks) was less than previously studied [29]–[31]. We also studied changes in release and turnover of extracellular dopamine by microdialysis.…”

Behavioral effects of subchronic inorganic manganese exposure in rats

“…In our experiments, a decrease in the spontaneous horizontal and local activity developed after 10 weeks of MnCl 2 exposure, indicating that both serotoninergic and dopaminergic control was probably affected by Mn [Subhash and Padmashree, 1991]. Mn-induced lesion of the nuclei in the hypothalamic lateral area could have contributed to body weight loss and altered motility [Dorman et al, 2000], observed simultaneously from the 6th treatment week to the 1st posttreatment week.…”

Brain Accumulation and Toxicity of Mn(II) and Mn(III) Exposures

“…In summary, the cumulative dose range of manganese used here (30-90 mg Mn/kg body weight) is at the lower range of exposures used in studies reporting adverse effects in rodents (Bonilla and Prasad, 1984;Chandra and Shukla, 1981;Eriksson et al, 1987;Gwiazda et al, 2002;Subhash and Padmashree, 1991). Exposures to Mn(III) produced higher blood and brain manganese concentrations than equimolar exposures to Mn(II), though there were no measurable differences in the manganese accumulation across the four brain regions examined here.…”

Iron-Responsive Olfactory Uptake of Manganese Improves Motor Function Deficits Associated with Iron Deficiency

“…Under our study conditions, DAT levels were the same in control and iron-deficient rats, but protein levels were reduced by olfactory manganese exposure in both groups. Similar effects of manganese exposure have been reported in studies of chronic administration by diet [29] or injection [30]. Our study indicates olfactory administration of manganese can also down-regulate DAT, possibly in a more acute manner.…”

“…While some investigations have shown that tissue dopamine levels are altered by iron deficiency, differences in age, circadian cycle, extent of iron depletion, and duration of low iron status between various study groups have led to inconsistent results [5], [7], [10], [11], [28]. Likewise, chronic manganese exposure to the brain across the blood-brain-barrier is thought to diminish dopamine levels [29]–[31], but the olfactory exposure used in our study did not appear to perturb dopamine content, possibly because metal accumulation was lower, manganese deposition was regionally different, and/or the duration of manganese exposure (1–3 weeks) was less than previously studied [29]–[31]. We also studied changes in release and turnover of extracellular dopamine by microdialysis.…”

Behavioral effects of subchronic inorganic manganese exposure in rats

“…In our experiments, a decrease in the spontaneous horizontal and local activity developed after 10 weeks of MnCl 2 exposure, indicating that both serotoninergic and dopaminergic control was probably affected by Mn [Subhash and Padmashree, 1991]. Mn-induced lesion of the nuclei in the hypothalamic lateral area could have contributed to body weight loss and altered motility [Dorman et al, 2000], observed simultaneously from the 6th treatment week to the 1st posttreatment week.…”

Brain Accumulation and Toxicity of Mn(II) and Mn(III) Exposures

“…In summary, the cumulative dose range of manganese used here (30-90 mg Mn/kg body weight) is at the lower range of exposures used in studies reporting adverse effects in rodents (Bonilla and Prasad, 1984;Chandra and Shukla, 1981;Eriksson et al, 1987;Gwiazda et al, 2002;Subhash and Padmashree, 1991). Exposures to Mn(III) produced higher blood and brain manganese concentrations than equimolar exposures to Mn(II), though there were no measurable differences in the manganese accumulation across the four brain regions examined here.…”