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Brain

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Full-Text Articles in Toxicology

Manganese Distribution Across The Blood-Brain Barrier. Iv. Evidence For Brain Influx Through Store-Operated Calcium Channels, Janelle S. Crossgrove, Robert A. Yokel Jun 2005

Manganese Distribution Across The Blood-Brain Barrier. Iv. Evidence For Brain Influx Through Store-Operated Calcium Channels, Janelle S. Crossgrove, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is a required co-factor for many ubiquitous enzymes; however, chronic Mn overexposure can cause manganism, a parkinsonian-like syndrome. Previous studies showed Mn influx into brain is carrier-mediated, though the putative carrier(s) were not established. Studies conducted with cultured bovine brain microvascular endothelial cells (bBMECs), which comprise the blood–brain barrier, revealed 54Mn (II) uptake positively correlated with pH, was temperature-dependent, and was sodium- and energy-independent. Brain 54Mn uptake correlated inversely with calcium (Ca) concentration, but 45Ca uptake was unaltered by high Mn concentration. Lanthanum (La), a non-selective inhibitor of several Ca channel types, as well as …


Manganese Distribution Across The Blood-Brain Barrier. I. Evidence For Carrier-Mediated Influx Of Managanese Citrate As Well As Manganese And Manganese Transferrin, Janelle S. Crossgrove, David D. Allen, Bonny L. Bukaveckas, Susan S. Rhineheimer, Robert A. Yokel Jan 2003

Manganese Distribution Across The Blood-Brain Barrier. I. Evidence For Carrier-Mediated Influx Of Managanese Citrate As Well As Manganese And Manganese Transferrin, Janelle S. Crossgrove, David D. Allen, Bonny L. Bukaveckas, Susan S. Rhineheimer, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is an essential element and a neurotoxicant. Regulation of Mn movement across the blood–brain barrier (BBB) contributes to whether the brain Mn concentration is functional or toxic. In plasma, Mn associates with water, small molecular weight ligands and proteins. Mn speciation may influence the kinetics of its movement through the BBB. In the present work, the brain influx rates of 54Mn2+, 54Mn citrate and 54Mn transferrin (54Mn Tf) were determined using the in situ brain perfusion technique. The influx rates were compared to their predicted diffusion rates, which were determined from …


The Toxicology Of Aluminum In The Brain: A Review, Robert A. Yokel Oct 2000

The Toxicology Of Aluminum In The Brain: A Review, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Aluminum is environmentally ubiquitous, providing human exposure. Usual human exposure is primarily dietary. The potential for significant Al absorption from the nasal cavity and direct distribution into the brain should be further investigated. Decreased renal function increases human risk of Al-induced accumulation and toxicity. Brain Al entry from blood may involve transferrin-receptor mediated endocytosis and a more rapid process transporting small molecular weight Al species. There appears to be Al efflux from the brain, probably as Al citrate. There is prolonged retention of a fraction of Al that enters the brain, suggesting the potential for accumulation with repeated exposure. Al …