Heterogeneity of morphological and functional changes in various compartments of rat urinary bladder in infravesical obstruction of the urinary tract.

Infravesical obstruction of the lower urinary tract was simulated in rats by dosed constriction of the prevesical portion of the urethra. The functional and morphological changes in various urinary bladder compartments were evaluated after 1 week and 3 months. The development of compensatory hypertrophy of the detrusor was associated with an increase in the number of hypertrophic, atrophic, and young leiomyocyte forms and their transformation into myofibroblasts, with the formation of connective tissue laminae between myofibril bundles mainly in the zone of urinary urinary bladder neck. Specific contractility of the detrusor strips decreased with increasing their tone, which was most pronounced in the neck zone. The relaxing effect of norepinephrine was significantly lower after 3 months of obstruction and virtually disappeared in the zone of the urinary bladder body and neck. Blockade of a-adrenoceptors after adrenostimulation with norepinephrine stimulated contractions of the hypertrophic detrusor against the background of reduced tone of the urinary bladder neck, in contrast to intact urinary bladder where this treatment reduced contractions.