Selective Inflammatory Pain Insensitivity in the African Naked Mole-Rat (Heterocephalus glaber)
(A) Photograph showing the similar overall size of the animals as well as the similar size of the hind feet, which are innervated by the saphenous nerve.
(B) Representative electron micrographs showing unmyelinated axons within Remak bundles (yellow arrows) and myelinated axons (red arrows) in saphenous nerves from the mouse and naked mole-rat (NMR). Scale bar = 2.0 μm.
(C) At higher magnification, single unmyelinated fibers can be distinguished within the Remak bundles. Scale bar = 2.0 μm.
(D) Quantification of myelinated and unmyelinated axon numbers in mouse (n = 6) and naked mole-rat (n = 4) saphenous nerves. Note that here and in subsequent figures, red bars denote data from mouse and gray bars indicate data from naked mole-rats.
(E and F) Proportion of cultured sensory cells that label with IB4 in mice (E) and naked mole-rats (F). Distributions are based on soma area, and C-cells have soma areas less than 600 μm2.