Fig. 1

Intraplantar injection of formalin activates SDH astrocytes via α_1A-ARs through descending LC-NAergic signals. a Averaged trace and AUC during the first 600 s (AUC_0–600 s) of astrocytic Ca²⁺ signals in the SDH after intraplantar injection of vehicle or formalin (vehicle, n = 47 ROIs, 4 mice; formalin, n = 123 ROIs, 4 mice, ****P < 0.0001, Mann–Whitney U test). b Schematic illustration of retrograde transduction strategy in descending LC-NAergic neurons using the FLEX-switch system. c Representative images of LC-NAergic neurons in mice treated with PBS or DTX administration. GFP (green), and TH (red). d–f SDH astrocytic Ca²⁺ responses by formalin in mice with ablation of descending LC-NAergic neurons (d), conditional knockout of α_1A-ARs in Hes5⁺ astrocytes (Adra1a-cKO; Hes5-CreERT2;Adra1a^flox/flox) compared with control mice (control; Adra1a^flox/flox) (e), and pretreatment intrathecally with PBS or silodosin (3 nmol) (f). Percentage of responding astrocytes (d control, n = 6 mice; ablated, n = 6 mice; e: control, n = 5 mice; Adra1a-cKO, n = 5 mice; f PBS, n = 6 mice; silodosin, n = 6 mice, *P < 0.05, **P < 0.01, ****P < 0.0001, unpaired t-test); averaged trace and AUC (d control, n = 255 ROIs; ablated, n = 263 ROIs; e control, n = 253 ROIs; Adra1a-cKO, n = 224 ROIs; f PBS, n = 364 ROIs; silodosin, n = 296 ROIs, ****P < 0.0001, Mann–Whitney U test). Data show the mean ± SEM