(A) Representative images of immunofluorescence staining with anti-TRPV1 (Green), anti-SP (Red), and DAPI (DNA; blue) from thoracic dorsal gray matter of Control, MCT and SuHx rats. Lower panel shows enlarged view of TRPV1 and SP colocalization (Yellow). N=3 per group. (B) Quantification of TRPV1 and SP immunolocalization (IOD: integrated optical density) in MCT and SuHx rats compared to controls. N=3 per group. ****p<0.0001. (C) Representative immunofluorescence images of TRPV1 (Green), SP (Red), and DAPI (DNA; blue) from thoracic dorsal gray matter of Control and PAH patients. Lower panel shows enlarged view of TRPV1 and SP colocalization (Yellow). N=3 per group. (D) Change in RVSP and heart rate after RV-epicardial and pulmonary vascular application of bradykinin (60 μg/mL) in Control and MCT rats. N=5 per group. *p<0.05, ***p<0.001.