Nerve growth factor (NGF) expressions in the neuronal voiding centers. Upper panel: photomicrographs of NGF-stained cells in neuronal voiding centers. The scale bar represents 150 µm (MPA, medial preoptic area; vlPAG, ventrolateral periaqueductal gray; PMC, pontine micturition center) and 200 µm (spinal cord L4–5). Sham, sham-operation group; BPH, benign prostatic hyperplasia; BPH-Tam, BPH-induced and tamsulosin-treated group; BPH-Nafto, BPH-induced and naftopidil-treated group; BPH-Combi, BPHinduced and combination-treated group. Lower panel: number of NGF-stained cells in each group. A, sham-operation group; B, benign prostatic hyperplasia (BPH)-induced group; C, BPH-induced and tamsulosin-treated group; D, BPH-induced and naftopidiltreated group; E, BPH-induced and combination-treated group. *P<0.05 compared to the sham-operation group. #P<0.05 compared to the BPH-induced group.