Co-expression of heat sensitive vanilloid receptor subtypes in rat dorsal root ganglion neurons.
Expression of the heat sensitive cation channels TRPV1 and TRPV2 was investigated by immunofluorescence in rat dorsal root ganglion (DRG) neurons. TRPV1-positive neurons were more frequent and had smaller diameters than TRPV2-positive neurons (35.7% vs 7.3%; 22.3 microm vs 27.6 microm), but size distributions overlapped and significant co-expression was seen in 20.7% of TRPV2-positive neurons (1.7% of all). Expression patterns did not differ between tissue sections typically used in immunocytochemistry and dissociated DRG neurons typically used in electrophysiology. Rectangular temperature pulses revealed two patterns of heat-evoked inward currents in small DRG neurons: low-threshold rapidly activating and high-threshold slowly activating. Slowly activating heat-evoked currents have not been described previously, but correspond to the type I heat responses of primary nociceptive afferents, which have been suggested to be mediated by TRPV2.
Greffrath
Wolfgang
W
Institute of Physiology and Pathophysiology, Johannes Gutenberg University, Mainz, Germany.
Binzen
Uta
U
Schwarz
Stefan T
ST
Saaler-Reinhardt
Sigrid
S
Treede
Rolf-Detlef
RD
D000818:Animals; D005727:Ganglia, Spinal / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006358:Hot Temperature; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000096:biosynthesis*; D050916:TRPV Cation Channels
D011955:Receptors, Drug; D050916:TRPV Cation Channels; C494484:TRPV1 receptor