Age-related changes in urinary bladder intramural neurons

A quantitative morphometric evaluation of the intramural plexus of the urinary bladder of adult and aged guinea-pigs was performed by histological analysis, scanning electron microscopy, and hystochemical methods, such as NADH-diaphorase and acetylcholinesterase (AChE). The round or oval shaped intramural neurons were revealed among the bundles of the smooth detrusor muscle in clusters containing a variable number of cells in the groups. In both adult control and aged animals, the ganglia were enveloped by a ganglionar capsule of connective tissue mainly composed of type I collagen fibers. The number of neurons NADH-diaphorase positives estimated in the intramural plexus was 1433 ± 187.71 and 1107 ± 120.67 in the adult control and aged groups, respectively. The perikaryon areas of the NADH-diaphorase neurons reactives ranged from 216.40 to 1809.30 μm2 in adult control group and from 198.20 to 2096.25 μm2 in aged group. The nuclear area showed an increase in aged animals. The number of AChE-positive neurons estimated in the intramural plexus was 3294.67 ± 415 μm2 in the adult control group and 1960.33 ± 526 μm2 in the aged group, showing a significant decrease in the latter group. This age-related morphological change in intramural neurons may contribute to changes in urinary bladder activities in the elderly.