1986 Volume 77 Issue 8 Pages 1237-1244
Functional behavior of superficial cells of the rat urinary bladder, in the contracted and experimentaly expanded conditions, was observed on thin section and freeze fracture replicas using electron microscopic techniques.
1. Luminal plasma membrane, which consists of characteristic asymmetric unit membrane, appeared jagged in the contracted state and in a scalloped shape in the expanded state without fine elemental modifications.
2. Intracytoplasmic discoid or fusiformed vesicles, observed below the free luminal plasma membrane in the contracted state, decreased in number, step by step, in expanded groups. Fusion of vesicles to plasma membrane was observed occasionally.
3. Junctional complex with neighbouring epithelial cells resembles to that of various kinds of epithelia in animals described in the literature: its complex showed no complete destruction and/or disposition between the contractd nd expanded states. The exception was the only partial discontinuation of intramembranous particles in the peripheral area in more expanded group observed on replica figures.
4. Characteristic were fused and parallel arrangement of interdigitation to the luminal surface in the experimentally expaned state, with which membrane complexicity may act as a certain functional barrier to prevent the penetration of urine contents through cells.
