Author/Editor		Jezernik, K
Title		Asymmetric membranes and the permeability barrier of the developing mammalian urinary bladder
Type		članek
Source		Acta Pharm
Vol. and No.		Letnik 42, št. 4
Publication year		1992
Volume		str. 287-91
Language		eng
Abstract		The formation of asymmetric unit membranes (AUMs) and the blood-urine permeability barrier was studied in differentiating mouse transitional urothelium using morphological and cytochemical electron microscopic techniques. It was established that the barrier development is a two phase process: it begins with the tight junction formation and is followed by the formation of asymmetric unit membranes in fusiform vesicles and apical plasmalemma. The development of AUMs is accompanied by the appearance of WGA binding sites. In fusiform vesicles AUMs are located on the large lateral plaque surface areas, while cholesterol rich-intramembrane particles free regions are found on the edge of discoidal compartments. Before the excretion of hypertonic urine into the embryonic bladder, fusiform vesicles and the apical plasmalemma fuse only by their interplaque regions. Some degenerative superficial cells apparently to slough in the late fetal days. Consequently, on some focal areas the bladder epithelium lacks an effective permeability barrier.
Descriptors		BLADDER EPITHELIUM MICE CELL MEMBRANE PERMEABILITY MICROSCOPY, ELECTRON EMBRYO