T-type calcium channels, but not Cav3.2, in the peripheral sensory afferents are involved in acute itch in mice.

ABSTRACT

T-type calcium channels are prominently expressed in primary nociceptive fibers and well characterized in pain processes. Although itch and pain share many similarities including primary sensory fibers, the function of T-type calcium channels on acute itch has not been explored. We investigated whether T-type calcium channels expressed within primary sensory fibers of mouse skin, especially Cav3.2 subtype, involve in chloroquine-, endothelin-1- and histamine-evoked acute itch using pharmacological, neuronal imaging and behavioral analyses. We found that pre-locally blocking three subtypes of T-type calcium channels in the peripheral afferents of skins, yielded an inhibition in acute itch or pain behaviors, while selectively blocking the Cav3.2 channel in the skin peripheral afferents only inhibited acute pain but not acute itch. These results suggest that T-type Cav3.1 or Cav3.3, but not Cav3.2 channel, have an important role in acute itch processing, and their distinctive roles in modulating acute itch are worthy of further investigation.