| Abstract: | The pattern of autonomic innervation of the urinary bladder was studied in the cat, dog, rabbit and rat, using specific histochemical technics for acetylcholinesterase and norepinephrine. Cholinergic and adrenergic ganglion cells exist in all layers throughout the bladder wall. Large cholinergic and adrenergic nerve trunks coursing in the adventitial coat and deep lamina propria branch into the muscularis. The terminal cholinergic ramifications form a neuroterminal plexus which surrounds every smooth muscle cell in the bladder wall. The terminal adrenergic fibers are less abundant, do not form a plexus, and show regional variations in number at different levels and depths of the muscularis. These variations suggest that two regions of the bladder, namely the base and body, may be distinguished on the basis of differences in muscular innervation. In the lamina propria cholinergic and adrenergic nerves are grouped as deep and superficial subepithelial nerves. The latter form networks of variable complexity and supply fibers to the epithelium. Throughout the bladder wall, the blood vessels have a dual cholinergic and adrenergic perivascular plexus from which fibers extend into the media. Although the basic pattern of innervation is similar in the species studied, certain variations exist in the relative abundance and arrangement of epithelial and subepithelial nerves. The muscularis has a uniform cholinergic and a variable adrenergic innervation in different species. |
