Kv1.2-immunoreactive primary sensory neurons in the rat trigeminal ganglion.
Immunohistochemistry for Kv1.2, a subunit of voltage-gated K(+) channels, was performed on the trigeminal ganglion (TG). Immunoreactivity (ir) was detected in half (48%) the TG neurons. These neurons were mostly medium-sized to large (range 137.6-2664.8 microm(2), mean+/-S.D. 892.6+/-413.3 microm(2)). A double immunofluorescence method also revealed co-expression of Kv1.2 and parvalbumin. Half (54%) the Kv1.2-immunoreactive (ir) neurons exhibited parvalbumin-ir, and parvalbumin-ir neurons mostly showed Kv1.2-ir (95%). Kv1.2-ir neurons which co-expressed CGRP-ir were rare in this ganglion. Some 40% of TG neurons retrogradely labeled from the facial skin exhibited Kv1.2-ir, whereas ir was detected in 16% of those labeled from the tooth pulp. The present study indicates that Kv1.2-ir TG neurons include low-threshold mechanoreceptors and nociceptors which innervate the facial skin and tooth pulp, respectively.
Ichikawa
Hiroyuki
H
Department of Oral Anatomy and Function, and Biodental Research Center, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Japan. hiroichi@md.okayama-u.ac.jp
Sugimoto
Tomosada
T
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D048429:Cell Size; D003782:Dental Pulp / Q000294:innervation; D005455:Fluorescent Antibody Technique; D051663:Kv1.2 Potassium Channel; D008297:Male; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D010320:Parvalbumins / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000294:innervation; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism*
C496972:Kcna2 protein, rat; D051663:Kv1.2 Potassium Channel; D010320:Parvalbumins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015740:Calcitonin Gene-Related Peptide