Is Selectively Expressed in Small Diameter Mouse DRG Neurons Distinct From Neurons Strongly Expressing .

Using a high resolution hybridization technique we have measured , , and transcripts in mouse dorsal root ganglion (DRG) neurons. Consistent with previous studies, transcripts were highly expressed in DRG neurons of all sizes, including most notably the largest diameter neurons implicated in mediating touch and proprioception. In contrast, transcripts were selectively expressed in smaller DRG neurons, which are implicated in mediating nociception. Moreover, the small neurons expressing were mostly distinct from those neurons that strongly expressed , one of the channels implicated in heat-nociception. Interestingly, while and expressing neurons form essentially non-overlapping populations, showed co-expression in both populations. Using an functional test for the selective expression, we found that Yoda1, a PIEZO1-specific agonist, induced a mechanical hyperalgesia that displayed a significantly prolonged time course compared with that induced by capsaicin, a TRPV1-specific agonist. Taken together, our results indicate that PIEZO1 should be considered a potential candidate in forming the long sought channel mediating mechano-nociception.