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.
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
Hiroyuki
H
Ichikawa
Tomosada
T
Sugimoto
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