Urethra afferents in the 3D reconstructed lumbosacral spinal cord.

Cholera toxin B (CTB) was injected into the wall of the urethra of male and female rats to visualize central projections of sensory axons in the spinal cord. This also labelled preganglionic neurons of the sacral preganglionic nucleus and, in females, external urethral sphincter motoneurons that were rarely labelled in males. Alternating lumbosacral spinal cord cryosections were immunolabelled for CTB and choline acetyltransferase (ChAT). These sections were digitally aligned in TissueMaker (MBF Bioscience). Pes9, ExU9: pes and external urethral sphincter motoneurons of lamina 9.