Adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from patients with spinal cord injury.

The adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from spinal cord injury patients with detrusor sphincter dyssynergia were investigated neurochemically and histochemically. Catecholamine fluorescence histochemistry provided no evidence for the presence of adrenergic nerves associated with the skeletal muscle. The noradrenaline content of this region probably reflects the endogenous levels in adrenergic nerves associated with the blood vessels supplying the skeletal muscle. Choline acetyltransferase activity in the skeletal muscle was significantly lower in patients with cervical lesions than in those with thoracic lesions (p less than 0.01). The noradrenaline content of the smooth muscle was significantly lower in cervical lesions than in thoracic lesions in both the mid (p less than 0.02) and the distal (p less than 0.001) regions of the urethra. The proximal region revealed similar noradrenaline levels in both groups of spinal cord injury patients. The results are discussed in relation to the role of the autonomic nervous system in the control of voiding and to the presence of increased sympathetic outflow in patients with spinal cord lesions at higher levels.