Tissue distribution of capsaicin receptor in the various organs of rats

Capsaicin receptor (vanilloid receptor 1, VR1), a cation channel, has been recently cloned and shown to be expressed in a subset of sensory neurons (C aterina et al., 1997, Nature 389, 816-824). To examine the distribution of VR1 on the protein level in the whole body, we produced an antiserum agains t bacterially expressed VR1. Immunoblot analysis revealed that VR1 was expr essed in not only nervous tissues including brain but tongue, esophagus, di aphragm, and leg muscle. In these tissues, VRI mRNA was also expressed (con firmed by RT-PCR). The significance of the expression in these muscles was discussed.