Expression of the small conductance Ca2+-activated K+ channel, SK3, in the olfactory ensheathing glial cells of rat brain.
Olfactory sensory neurons are wrapped by ensheathing glial cells in the olfactory nerve layer (ONL). Neither functional roles nor electrical properties of ensheathing glial cells have been, as yet, fully clarified. Four subunits (SK1-4) of small conductance Ca2+-activated K+ (SK) channels have been cloned. In the present study, immunohistochemical analyses showed that SK3 channels are expressed in ensheathing glial cells in the rat olfactory bulb, in addition to neuronal cells in other regions. Western blotting analysis demonstrated that SK3 was predominantly expressed in the olfactory bulb, thalamus, moderately in the hippocampus and cerebellum and modestly in the cerebral cortex of the rat brain. SK3 immunoreactivity was detected in the ONL of the olfactory bulb, neural cell body and fibers of the substantia nigra and hypothalamus. SK3 immunoreactivity was quite intense in the outer (superficial) part of the ONL. SK3-immunoreactive structures were overlapped with glial fibrillary acidic protein (GFAP), but not with vimentin, markers for glial cells and olfactory sensory axons, respectively. Immunoelectron microscopy showed that SK3 immunoreactivity was localized in thin processes that enfolded fascicles of immunonegative olfactory nerve axons. These results indicate that SK3 is expressed specifically in the olfactory ensheathing glial cells in olfactory regions.
Fujita
Akikazu
A
Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, Osaka Prefecture University, 1-1 Gakuencho, 599-8531 Sakai, Osaka, Japan. afujita@vet.osakafu-u.ac.jp
Takeuchi
Tadayoshi
T
Hanai
Jun
J
Hata
Fumiaki
F
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D009830:Olfactory Bulb / Q000166:cytology / Q000378:metabolism*; D009832:Olfactory Nerve / Q000502:physiology; D018034:Olfactory Receptor Neurons / Q000166:cytology* / Q000648:ultrastructure; D015221:Potassium Channels / Q000032:analysis / Q000378:metabolism*; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D051381:Rats; D051640:Small-Conductance Calcium-Activated Potassium Channels
C496896:Kcnn1 protein, rat; C496901:Kcnn3 protein, rat; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D051640:Small-Conductance Calcium-Activated Potassium Channels