A T-type calcium channel required for normal function of a mammalian mechanoreceptor

The dorsal root ganglia (DRG) contain a variety of mechanoreceptors, but no molecular markers uniquely identify specific mechanoreceptor subtypes. We have used DNA microarrays and subtracted cDNA libraries to isolate genes that are specifically expressed by one type of mouse mechanoreceptor. The T-type calcium channel Ca(v)3.2 was exclusively expressed in the DRG by D-hair receptors, a very sensitive mechanoreceptor. Pharmacological blockade of T-type calcium channels indicated that this channel may be essential for normal D-hair receptor excitability including mechanosensitivity. This is the first evidence that a calcium channel is required for normal function of a vertebrate mechanoreceptor.