Investigation for urinary urgency with dorsal root ganglion neurons projecting dichotomizing axons to both skin and bladder

为了揭示冷感觉引起尿急的机制，我们研究了皮肤和膀胱的初级感觉传入神经的收敛性。用逆行神经元示踪剂连续观察大鼠支配皮肤和膀胱的L6-S1背根神经节神经元的传入事件分化。原位杂交显示，约8.0%的双标记细胞在背根神经节中表达瞬时受体电位通道美拉他汀成员8 （TRPM8）转录物。低温和薄荷醇刺激皮肤产生的膀胱神经反应通过轴突二分性传导，在TRPM8阻滞剂BCTC存在下显著降低。综上所述，表达trpm8且轴突向皮肤和膀胱的感觉神经元可能与冷感觉引起的尿急有关。

In order to reveal the mechanism of urinary urgency evoked by cold sensation, we investigated the convergence of the primary sensory afferents of the skin and bladder. Dichotomizing afferents of L6-S1 dorsal root ganglion neurons that innervate the skin and bladder was constantly observed with retrograde neuron tracers in rats. In-situ hybridization revealed that approximately 8.0% of the double-labelled cells expressed transient receptor potential channel melastatin member 8 (TRPM8) transcripts in the dorsal root ganglions. Cold and menthol stimuli to the skin generated bladder nerve responses conducted through dichotomizing axons, which significantly decreased in the presence of the TRPM8 blocker BCTC. In conclusion, TRPM8-expressing sensory neurons with dichotomizing axons projecting to the skin and bladder may be responsible for the urinary urgency evoked by cold sensation.