M.D. University of Oslo, 1993
Ph.D. University of Oslo, 1998

In his thesis Erlend A. Nagelhus described that the brain contains the water channel aquaporin-4 (AQP4). The work was done in Professor
Ole Petter Ottersen`s lab in collaboration with Professor Peter Agre (Nobel Prize laureate 2003), Baltimore, and Professor Søren Nielsen, Aarhus. In a series of papers using high resolution pre- and postembedding immunogold cytochemistry the authors unraveled the detailed localization of AQP4 in the central nervous system. The
papers showed that AQP4 is enriched in glial endfeet facing blood vessels and the pial surface (see illustration below). The concept that astrocytes are polarized cells was also proven for Kir4.1, an inwardly rectifying potassium channel, suggesting a link between water flux
and potassium conductance. After some years in clinical medicine - with training in child neurology - he returned to the lab. Research field: water homeostasis in the central nervous system.

The water channel aquaporin-4 is abundant in glial endfoot processes abutting on cerebral blood vessels. This is shown by the immunogold technique (upper panel). Illustration: Erlend Nagelhus and Gunnar Lothe. 3D MRI: Kyrre Eeg Emblem, Rikshospitalet, and Inge Rasmussen, Nidelven Hjerneforskningslaboratorium.

Selected papers:

1: Nagelhus EA, Mathiisen TM, Bateman AC, Haug FM, Ottersen OP, Grubb JH, Waheed A, and Sly WS.
Carbonic anhydrase XIV is enriched in specific membrane domains of retinal pigment epithelium, Müller cells, and astrocytes.
Proc Natl Acad Sci U S A. 2005 May 31;102(22):8030-5. Epub 2005 May 18.

2: Wen H*, Nagelhus EA*, Amiry-Moghaddam M, Agre P, Ottersen OP, Nielsen S.
Ontogeny of water transport in rat brain: postnatal expression of the aquaporin-4 water channel.
European Journal of Neuroscienc 1999 Mar;11(3):935-45. (*Wen & Nagelhus contributed equally)

3: Nagelhus EA, Horio Y, Inanobe A, Fujita A, Haug FM, Nielsen S, Kurachi Y, Ottersen OP.
Immunogold evidence suggests that coupling of K+ siphoning and water transport in rat retinal
Muller cells is mediated by a coenrichment of Kir4.1 and AQP4 in specific membrane domains.
Glia. 1999 Mar;26(1):47-54.

4: Nagelhus EA, Veruki ML, Torp R, Haug FM, Laake JH, Nielsen S, Agre P, Ottersen OP.
Aquaporin-4 water channel protein in the rat retina and optic nerve: polarized expression in Muller cells and fibrous astrocytes.
J Neurosci. 1998 Apr 1;18(7):2506-19.

5: Nielsen S*, Nagelhus EA*, Amiry-Moghaddam M, Bourque C, Agre P, Ottersen OP.
Specialized membrane domains for water transport in glial cells: high-resolution immunogold cytochemistry of aquaporin-4 in rat brain.
J Neurosci. 1997 Jan 1;17(1):171-80. (*Nielsen & Nagelhus contributed equally)