doi:10.1369/jhc.2008.950303
Volume 56 (5): 443-465, 2008 Copyright ©The Histochemical Society, Inc. Voltage-gated Potassium Channel (Kv) Subunits Expressed in the Rat Cochlear Nucleus
Department of Physiology, Research Centre of Molecular Medicine, Medical and Health Science Centre, University of Debrecen, Debrecen, Hungary (ZR,GB,KP,LK,BP,DN,GS), and Department of Pathology, Hajdú-Bihar Megyei Kenézy Gyula County Infirmary, Debrecen, Hungary (ÁP)
Correspondence to: Géza Sz Because the neuronal membrane properties and firing characteristics are crucially affected by the depolarization-activated K+ channel (Kv) subunits, data about the Kv distribution may provide useful information regarding the functionality of the neurons situated in the cochlear nucleus (CN). Using immunohistochemistry in free-floating slices, the distribution of seven Kv subunits was described in the rat CN. Positive labeling was observed for Kv1.1, 1.2, 1.6, 3.1, 3.4, 4.2, and 4.3 subunits. Giant and octopus neurons showed particularly strong immunopositivity for Kv3.1; octopus neurons showed intense Kv1.1- and 1.2-specific reactions also. In the latter case, an age-dependent change of the expression pattern was also documented; although both young and older animals produced definite labeling for Kv1.2, the intensity of the reaction increased in older animals and was accompanied with the translocation of the Kv1.2 subunits to the cell surface membrane. The granule cell layer exhibited strong Kv4.2-specific immunopositivity, and markedly Kv4.2-positive glomerular synapses were also seen. It was found that neither giant nor pyramidal cells were uniform in terms of their Kv expression patterns. Our data provide new information about the Kv expression of the CN and also suggest potential functional heterogeneity of the giant and pyramidal cells. (J Histochem Cytochem 56:443–465, 2008)
Key Words: hearing rhodamine immunohistochemistry confocal microscopy age dependence glomerular synapse
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