Locations of T-type channels in the ascending afferent pain pathway. In rodents, T-type channels (green) are present surrounding D-hair mechanoreceptors, on both C and Aδ afferent fibers, on C and Aδ DRG somata, on C fiber presynaptic terminals, and on both lamina I and II neurons within the superficial dorsal horn. Insets indicate key experiments defining the presence of T-type channels in different compartments. a Expression of Cav3.2 fused to GFP in C and Aδ mouse sciatic nerve fibers. Adapted with permission from Francois et al. . b Presence of low voltage-activated current in small diameter rat DRG neurons. Adapted with permission from Scroggs and Fox . c T-type calcium channels contribute to action potential-induced calcium current in the soma and dendrites of rat lamina I neurons. Adapted with permission from Harding et al.