Fig. 1

Kidney afferent nerves drive a kidney-to-brain neural circuit in normal mice. a, b Schematic for labeling presynaptic terminals of dorsal horn neurons that receive kidney afferent input a. Representative image shows injection site in the dorsal horn at T10 level (b, left). The representative image shows substantial presynaptic terminals of these dorsal horn neurons in the SFO (b, right). Scale bar, 100 µm. c Schematic for injection of AAV2/9-hSyn-DIO-mGFP-T2A-sysn-mRuby into the dorsal horn at T9-T11 level alone (upper). The representative image shows no labeled neurons observed in dorsal horn after virus injection (down). Scale bar, 100 µm. d Normal mice were subjected to kidney denervation before the virus injection (left). The representative image shows no labeling of dorsal horn neurons at T10 level, and no labeling of terminals of dorsal horn neurons in SFO, PVN, and RVLM post-virus injection in these mice (right). Scale bar, 100 µm. e, f Schematic for labeling terminals of SFO neurons that receive kidney spinal afferent input e. The representative image shows the injection site in the SFO (f, left). The representative image shows substantial presynaptic terminals of these SFO neurons in the PVN (f, right). Scale bar, 100 µm. g Schematic for injection of AAV2/9-hSyn-DIO-mGFP-T2A-sysn-mRuby into the SFO alone (upper). The representative image shows no labeled neurons observed in the SFO after virus injection (down). Scale bar, 100 µm. h, i Schematic for labeling direct innervation of SFO in RVLM-projecting PVN neurons h. Representative images showing DsRed-labeled neurons in RVLM, double-infected relay neurons in PVN, and DsRed-labeled neurons in SFO i. Scale bar, 100 µm. Error bars, mean ± SD. n = 3 in each experiment. Abbreviations for brain regions: SFO, subfornical organ (Bregma −0.70 mm); PVN paraventricular nucleus (Bregma −0.94 mm); RVLM rostral ventrolateral medulla (Bregma −6.72 mm)