Expression of the TRPM8-immunoreactivity in dorsal root ganglion neurons innervating the rat urinary bladder.
The neurochemical phenotypes of the transient receptor potential melastatin-8 (TRPM8)-immunoreactive afferent neurons innervating the rat urinary bladder were examined by using a highly sensitive tyramide signal amplification method, combined with wheat-germ agglutinin-horseradish peroxidase (WGA-HRP) retrograde tracing. TRPM8-immunoreactivity was detected in a small proportion of the WGA-HRP-labeled bladder afferent neurons in the dorsal root ganglia of the Th13-L1 (1.14%) and the L6-S1 (1.27%), and these neurons were small in size (<600 microm(2)). The 82.6+/-3.8% of the TRPM8-immunoreactive bladder afferent neurons and 80.9+/-1.5% of the total population of the TRPM8-immunoreactive afferent neurons in the observed dorsal root ganglia expressed NF200. On the other hand, the proportions of the co-expression of TRPM8 and nociceptive markers such as calcitonin gene-related peptide (CGRP), transient receptor potential vanilloid-1 (TRPV1), and isolectin B4 (IB4) in the bladder afferent neurons (81.5+/-5.2% for CGRP, 36.1+/-4.0% for TRPV1, and 15.8+/-5.5% for IB4) were higher in comparison to those in the total population of the TRPM8-immunoreactive afferent neurons (21.9+/-2.4% for CGRP, 16.6+/-1.7% for TRPV1, and 5.4+/-0.5% for IB4), although no significant difference existed for IB4. Our results suggest that the TRPM8-expressing bladder afferents should be classified as Adelta-fibers and C-fibers, while some of these afferents may be involved in nociceptive sensations.
Hayashi
Tokumasa
T
Department of Urology, Kurume University School of Medicine, Asahimachi 67, Kurume 830-0011, Fukuoka, Japan. hayashi_tokumasa@kurume-u.ac.jp
Kondo
Teruyoshi
T
Ishimatsu
Masaru
M
Yamada
Satoko
S
Nakamura
Kei-ichiro
K
Matsuoka
Kei
K
Akasu
Takashi
T
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002452:Cell Count; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D009413:Nerve Fibers, Myelinated / Q000378:metabolism / Q000648:ultrastructure; D036421:Nerve Fibers, Unmyelinated / Q000378:metabolism / Q000648:ultrastructure; D056347:Neuroanatomical Tract-Tracing Techniques / Q000379:methods; D016900:Neurofilament Proteins / Q000378:metabolism; D009619:Nociceptors / Q000166:cytology / Q000378:metabolism*; D010146:Pain / Q000378:metabolism / Q000503:physiopathology; D037121:Plant Lectins; D051381:Rats; D017208:Rats, Wistar; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000378:metabolism; D001743:Urinary Bladder / Q000294:innervation*; D017833:Visceral Afferents / Q000166:cytology / Q000378:metabolism*; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
D015415:Biomarkers; C045475:Griffonia simplicifolia lectins; D016900:Neurofilament Proteins; D037121:Plant Lectins; D050053:TRPM Cation Channels; D050916:TRPV Cation Channels; C498947:Trpm8 protein, rat; C493922:Trpv1 protein, rat; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; C051774:neurofilament protein H; D015740:Calcitonin Gene-Related Peptide