Brian Roland Larsen

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Network activity in the brain is associated with a transient increase in extracellular K(+) concentration. The excess K(+) is removed from the extracellular space by mechanisms proposed to involve Kir4.1-mediated spatial buffering, the Na(+)/K(+)/2Cl(-) cotransporter 1 (NKCC1), and/or Na(+)/K(+)-ATPase activity. Their individual contribution to [K(+)]o(More)
Epidemiological, cellular, and animal studies suggest that abnormalities in cholesterol metabolism may contribute to the etiology of Alzheimer's disease by increasing the generation of beta-amyloid (Abeta). However, the mechanism by which cholesterol increases Abeta levels is not fully understood. In the present study, we demonstrate that feeding rabbits(More)
Hypercholesterolemia is a potential trigger of Alzheimer's disease, and is thought to increase brain levels of beta-amyloid (Abeta) and iron. However, animal models to address the mechanisms by which Abeta and iron accumulation may cause neuronal damage are poorly defined. To address this question, we fed adult rabbits a 1% cholesterol-enriched diet for 7(More)
Neuronal activity results in release of K(+) into the extracellular space of the central nervous system. If the excess K(+) is allowed to accumulate, neuronal firing will be compromised by the ensuing neuronal membrane depolarization. The surrounding glial cells are involved in clearing K(+) from the extracellular space by molecular mechanism(s), the(More)
Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain-blood interface. AQP4 serves as a water entry site during brain edema formation, and regulation of AQP4 may therefore be of therapeutic interest. Phosphorylation of aquaporins can regulate plasma membrane(More)
Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain–blood interface. Based on studies on AQP4−/− mice, AQP4 has been assigned physiological roles in stimulus-induced K+ clearance, paravascular fluid flow, and brain edema formation. Conflicting data have been(More)
During neuronal activity in the brain, extracellular K(+) rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K(+) is the Na(+)/K(+)-ATPase, although the relative involvement and physiological impact of the different subunit isoform compositions of the Na(+)/K(+)-ATPase remain(More)
KEY POINTS Management of glutamate and K(+) in brain extracellular space is of critical importance to neuronal function. The astrocytic α2β2 Na(+) /K(+) -ATPase isoform combination is activated by the K(+) transients occurring during neuronal activity. In the present study, we report that glutamate transporter-mediated astrocytic Na(+) transients stimulate(More)
We have initiated a project designed to isolate and identify the neurohypophysial peptides found in the bovine pineal gland. Our principle interest is to provide definitive molecular evidence in order to eliminate the conflict created by the present literature as to the presence of arginine vasotocin in the mammalian pineal gland. The pineals were extracted(More)
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