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A prominent soma‐dendritic distribution of Kv3.3 K + channels in electrosensory and cerebellar neurons
Author(s) -
Rashid Asim J.,
Dunn Robert J.,
Turner Ray W.
Publication year - 2001
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.1409
Subject(s) - soma , biology , cerebellum , neuroscience , axon , efferent , granule cell , purkinje cell , anatomy , cerebellar cortex , climbing fiber , deep cerebellar nuclei , afferent , central nervous system , dentate gyrus
The expression pattern and subcellular distribution of a teleost homologue of the mammalian Kv3.3 potassium channel, Apt Kv3.3, was examined in the electrosensory lateral line lobe (ELL) and two cerebellar lobes in the hindbrain of the weakly electric gymnotiform Apteronotus leptorhynchus . Apt Kv3.3 expression was brain specific, with the highest level of expression in the cerebellum and 56% relative expression in the ELL. In situ hybridization revealed that Apt Kv3.3 mRNA was present in virtually all cell classes in the ELL as well as in the cerebellar lobes eminentia granularis pars posterior (EGp) and corpus cerebellum (CCb). Immunocytochemistry indicated a distribution of Apt Kv3.3 channels over the entire soma‐dendritic axis of ELL pyramidal, granule, and polymorphic cells and over the soma and at least proximal dendrites (100 μm) of multipolar cells and neurons of the ventral molecular layer. Apt Kv3.3 immunolabel was present at the soma of cerebellar granule, golgi, eurydendroid, and CCb Purkinje cells, with an equally intense label throughout the dendrites of CCb Purkinje cells and EGp eurydendroid cells. Immunolabel was virtually absent in afferent or efferent axon tracts of the ELL but was detected on climbing fiber axons and on the axons and putative terminal boutons of CCb Purkinje cells. These data reveal a prominent soma‐dendritic distribution of Apt Kv3.3 K + channels in both principal output and local circuit neurons, a pattern that is distinct from the soma‐axonal distribution that characterizes all other Kv3 K + channels examined to date. The widespread distribution of Apt Kv3.3 immunolabel in electrosensory cells implies an important role in several aspects of signal processing. J. Comp. Neurol. 441:234–247, 2001. © 2001 Wiley‐Liss, Inc.