Sympathetic innervation of the urinary bladder and urethral muscle in the pig

The sympathetic innervation of the lower urinary tract was studied in the female and male pig using a specific histochemical technique for visualization of noradrenaline containing nerves. In smooth muscle from the detrusor few evenly distributed adrenergic nerve terminals were found. A greater number of terminals were observed in the trigone, bladder neck and urethra. There was no sex difference. In smooth muscle specimens from pig detrusor and trigone sympathetic nerve terminals were more abundant than in corresponding tissue from humans.