Histochemistry of nerve fibres double labelled with anti-TRPV2 antibodies and sensory nerve marker AM1-43 in the dental pulp of rat molars.

AM1-43 can label sensory nerve fibres and sensory neurons. Permeation of non-selective cation channels of the nerve cell membrane is suggested to be the mechanism responsible for labelling. To identify these channels, two candidates, TRPV1 and TRPV2 were examined by immunocytochemistry in the dental pulp and trigeminal ganglion of rats injected with AM1-43. A part of AM1-43-labelled nerve fibres was also positive for anti-TRPV2 antibody but negative for anti-TRPV1 antibody in the dental pulp. In the trigeminal ganglion, a part of the neuron showed both bright AM1-43 labelling and anti-TRPV2 immunolabelling, but neurons double labelled with AM1-43 and TRPV1 were rare. These results suggest that TRPV2 channels, but not TRPV1 channels, contribute to the fluorescent labelling of AM1-43 in the dental pulp.