Supplementary Figure 2: Sstcre neurons innervate the skin and can be reliably activated using optogenetics.
From: Circuit dissection of the role of somatostatin in itch and pain
A, double label ISH reveals that in SstCre;Ai9 mice expression of tdTomato (tdT, magenta) occurs largely in Nppb-neurons (green). White arrows indicate Nppb-expressing neurons not expressing tdTomato, and the grey arrow indicates a tdTomato-positive neurons that does not express Nppb. Similar results were obtained from 3 mice. B, Somatostain-neurons innervate superficial layers of the skin. A section through the ear of a Sstcre;Ai9 mouse reveals tdTomato fibers (red) that are close to the surface of the skin (image is superimposed on a DIC-image to highlight the location of fibers); also see1,2 for evidence of cutaneous segregation of somatostatin-expressing afferents. C, Neurons from Sstcre;Ai32 mice can be optogenetically activated with a variety of frequencies of light stimulation. Cultured DRG-neurons from Sstcre;Ai32 were stimulated at 1, 5, 20, and 40 Hz and electrophysiological responses recorded under current (left panel), or voltage clamp (right panel) conditions. n=11/11 neurons responding, all neurons exhibited non-saturating responses up to 20Hz. 1. Molander, C., Ygge, J. & Dalsgaard, C.J. Substance P-, somatostatin- and calcitonin gene-related peptide-like immunoreactivity and fluoride resistant acid phosphatase-activity in relation to retrogradely labeled cutaneous, muscular and visceral primary sensory neurons in the rat. Neurosci Lett 74, 37-42 (1987). 2. O’Brien, C., Woolf, C.J., Fitzgerald, M., Lindsay, R.M. & Molander, C. Differences in the chemical expression of rat primary afferent neurons which innervate skin, muscle or joint. Neuroscience 32, 493-502 (1989).
