Distribution of TRPC channels in a visceral sensory pathway.
Until recently most of the published studies addressing the mechanisms of activation of TRPC channels have been carried out in heterologous expression systems. Lack of specific antagonists for the TRPC channels has hampered functional studies of endogenous channels. We approached the role of TRPC channels in native tissue with a study of the distribution of the channel proteins in the carotid chemosensory pathway in the rat. In a previous report we showed that TRPC3/4/5/6 and TRPC7 were present in neurons throughout the petrosal ganglion while TRPC1 was expressed in only a subpopulation of petrosal neurons, at least half of which projected to the carotid body. The TRPC proteins were differentially distributed to the branches of the axons that project centrally to the nucleus of the solitary tract and peripherally to the carotid body. The smallest unmyelinated sensory fibres projecting to the carotid body contained TRPC1/3/4/5 or TRPC6 but not TRPC7. TRPC1 and TRPC3 were concentrated in the larger diameter fibres. Interestingly, only TRPC1 and TRPC4 could be demonstrated in the final terminal endings within glomus cell clusters of the carotid body. In the central axon of the sensory neurons, both TRPC4 and TRPC5 were demonstrated in fibres exiting the solitary tract and projecting to the secondary relay neurons the nucleus of the solitary tract.
Buniel
Maria
M
Rammelkamp Center for Education and Research, MetroHealth Campus of Case Western Reserve University, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA.
Wisnoskey
Brian
B
Glazebrook
Patricia A
PA
Schilling
William P
WP
Kunze
Diana L
DL
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling; D002478:Cells, Cultured; D002628:Chemoreceptor Cells / Q000378:metabolism*; D017950:Ganglia, Sensory / Q000378:metabolism; D007124:Immunoenzyme Techniques; D009475:Neurons, Afferent / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018411:Spodoptera / Q000235:genetics; D050052:TRPC Cation Channels; D014781:Viscera / Q000378:metabolism*
D015220:Calcium Channels; D050052:TRPC Cation Channels