Cyclooxygenase-1 is a marker for a subpopulation of putative nociceptive neurons in rat dorsal root ganglia.
Immunocytochemical and morphometric techniques were used to quantify the distribution of cyclooxygenase (cox)-containing neurons in rat L5 dorsal root ganglia (DRG). Cox-1 immunolabelling was almost exclusively restricted to small diameter DRG neurons (< 1000 microm2), and was extensively colocalized with calcitonin gene-related peptide (CGRP) and isolectin B4 (IB4). Cox-1 was present in 65% and 70% of CGRP- and IB4-labelled neurons, respectively. Cox-1 labelling was also found in neurons expressing the sensory neuron-specific (SNS) Na+ channel. Cox-2 labelling was absent in DRG from normal rats. In the Freund's adjuvant model of monoarthritis, the proportion of cox-1-positive DRG neurons was unchanged and no neurons were found to be labelled for cox-2. In primary tissue culture, cox-1 immunolabelling persisted in vitro for up to 9 days and was present in morphologically identical neurons. The selective expression of cox-1 in peripheral ganglia was confirmed by the small number of nodose ganglion neurons and superior cervical ganglion (SCG) neurons labelled for cox-1. These data suggest that cox-1 is a marker for a subpopulation of putative nociceptive neurons in vitro and in vivo, and suggests that the prostaglandins synthesized by these neurons may be important for nociceptor function. These data may have important implications for the mode and mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs).
Chopra
B
B
Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK.
Giblett
S
S
Little
J G
JG
Donaldson
L F
LF
Tate
S
S
Evans
R J
RJ
Grubb
B D
BD
D000818:Animals; D001169:Arthritis, Experimental / Q000473:pathology; D015415:Biomarkers; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis; D002478:Cells, Cultured; D002772:Cholera Toxin; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D005724:Ganglia / Q000166:cytology / Q000201:enzymology; D005727:Ganglia, Spinal / Q000166:cytology / Q000201:enzymology*; D006735:Horseradish Peroxidase; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009475:Neurons, Afferent / Q000201:enzymology*; D009479:Neuropeptides / Q000378:metabolism; D009619:Nociceptors / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000378:metabolism
D015415:Biomarkers; D007527:Isoenzymes; D008565:Membrane Proteins; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009479:Neuropeptides; C568319:Scn10a protein, rat; D015222:Sodium Channels; C052635:cholera toxin, B subunit-horseradish peroxidase; D002772:Cholera Toxin; D006735:Horseradish Peroxidase; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496513:Ptgs1 protein, rat; D015740:Calcitonin Gene-Related Peptide