Extended Data Fig. 9: Hunger suppresses inflammatory pain by acting on Y1 receptors on lPBN neurons.
From: A parabrachial hub for need-state control of enduring pain
(a) (Top) Cre-dependent axon-enriched EGFP was injected in the dorsal horn and Cre-dependent tdTomato was injected into the lPBN of Npy1r-Cre mice to visualize neurons that express Npy1r and thus are potential pre- and post-synaptic sites of action of NPY in the lPBN. (Bottom) Representative images showing Y1R neurons expressing EGFP at the site of injection in the dorsal horn (left) and their projections to the lPBN along with lPBN Y1R neurons labeled with tdTomato (right). Scale bar, 200 μm (inset, 10 μm). (b) Diagram depicting two possible sites of action of NPY in the lPBN: presynaptic inputs from the spinal cord and postsynaptic receptors on lPBN neurons. (c) Y1 receptors were conditionally deleted from the spinal cord to reduce pre-synaptic signaling by crossing Npy1r-lox/lox mice with Lbx1-Cre mice32. Time spent licking paw in 5 min bins after an injection of formalin in ad libitum-fed and food-deprived mice (n = 6 mice, repeated measures two-way ANOVA, main effect of group p = 0.0144). (d) Y1 receptor expression was knocked down in the lPBN to reduce post-synaptic signaling by injecting an AAV expressing short hairpin RNA (shRNA) targeting the Npy1r gene. Inset shows shRNA-GFP expression in the lPBN. Scale bar, 200 μm. Time spent licking paw in 5 min bins after an injection of formalin in ad libitum-fed and food-deprived mice (n = 7 ad lib, n = 5 FD mice, repeated measures two-way ANOVA, n.s.). Data are expressed as mean ± SEM. ANOVA main effect of group: #p < 0.05.
