The ultrastructure and chemistry of the luminal plasma membrane of the mammalian urinary bladder: a structure with low permeability to water and ions.

摘要: The epithelium of the mammalian urinary bladder is an effective barrier to free flux urea, water and small charged ions between urine tissue fluids. In this paper we present evidence show that permeability passively depends on structure unusual, thick, rigid membrane which limits surface epithelial cells. normal unique. Thickened plaques, composed a hexagonal lattice dodecameric subunits extend through depth membrane, are separated by thinner, unstructured, narrow bands. regular may be disrupted or distorted treatment with guanidine hydrochloride sodium dodecyl sulphate. Chemically also remarkable. Its lipid component contains cerebroside, apparently has important effect in lowering permeability. This reinforced cholesterol, for maintenance condensed layer during mechanical stresses contraction dilation. protein unusual having high proline content, significance discussed context function. At moment it not possible relate marked subunit its although large particle mass mucoprotein compound, as yet uncharacterized, located densely staining, negatively lamina membrane. thus remarkable both These properties turn must depend complex interactions components themselves unusual.