Disease relevance of Permeability

• Cystic fibrosis (CF) is a lethal genetic disease resulting in a reduced Cl- permeability, increased mucous sulphation, increased Na+ absorption and defective acidification of lysosomal vesicles [1].
• Developmental and physiological signals have been identified that initiate the specific phosphorylation and dephosphorylation of these residues, regulating cadherin function during neurite outgrowth, permeability of airway epithelium and synapse remodeling, and possibly initiating epithelial cell migration during development and metastasis [2].
• In this report, TNF is shown to increase the permeability of endothelial cell monolayers to macromolecules and lower molecular weight solutes by a mechanism involving a pertussis toxin-sensitive regulatory G protein [3].
• Effects of the putative neutrophil-generated toxin, hypochlorous acid, on membrane permeability and transport systems of Escherichia coli [4].
• The regulation of cerebrovascular permeability is critical for normal brain homeostasis, and the "breakdown" of the blood-brain barrier (BBB) is associated with the development of vasogenic edema and intracranial hypertension in a number of neurological disorders [5].

Psychiatry related information on Permeability

• The effects of amitriptyline, lithium, and electroconvulsive shock on cerebral permeability and blood flow were tested [6].
• The primary lesion in Alzheimer's disease and dialysis dementia has been postulated to be an impaired blood-brain-barrier (BBB) permeability that allows neurotoxins like aluminium to reach the central nervous system [7].
• CONCLUSIONS: Psychological stress may increase gastrointestinal permeability, allowing luminal constituents access to the mucosal immune system [8].
• Therefore, these data show that modulation of BBB permeability to glucose is not a mechanism that provides 'energy on demand' during the physiologic brain activation characterising REM sleep [9].
• Since amyloid beta-protein (A beta) is the primary component of both vascular and parenchymal amyloid deposits in Alzheimer's disease, information regarding its permeability at the blood-brain barrier (BBB) will help elucidate the contribution of circulating A beta to vascular and parenchymal A beta deposition in this disease and in brain aging [10].

High impact information on Permeability

• Plasma leakage caused by release of some other permeability factor (including kinin made by tissue kallikrein) would thus lead to activation of the plasma cascade in many forms of inflammation [11].
• The high water permeability characteristic of mammalian red cell membranes is now known to be caused by the protein AQP1 [12].
• In many cells, activation of homomeric P2X7 receptors induces a permeability increase to larger organic cations including some fluorescent dyes and also signals to the cytoskeleton; these changes probably involve additional interacting proteins [13].
• A fiber matrix ultrafilter at the luminal entrance to the clefts is essential if microvascular walls are to retain their low permeability to macromolecules [14].
• Here, Na+ channels dominate, although a minor fraction of membrane permeability comes from K+ channels, as in frog skin, colon, or distal nephron [15].

Chemical compound and disease context of Permeability

• Cell cycle dependence of chloride permeability in normal and cystic fibrosis lymphocytes [16].
• Bradykinin production and increased pulmonary endothelial permeability during acute respiratory failure in unanesthetized sheep [17].
• Haemophilus influenzae lipopolysaccharide-induced blood brain barrier permeability during experimental meningitis in the rat [18].
• These results suggest that the protective effect of enalapril on the development of proteinuria and glomerular sclerosis in this model is due to its property of ameliorating size selectivity and hydraulic permeability of the glomerular capillaries [19].
• The inability of lactulose, rhamnose, or mannitol to detect permeability abnormalities in healthy relatives of patients with Crohn's disease suggests that these probes penetrate the intestinal barrier by routes or mechanisms that are different from those of polyethylene glycol 400 [20].

Biological context of Permeability

• Affected individuals in these families had an increase in membrane permeability to Na and K that is particularly marked at 0 degrees C. We found that disease in these pedigrees was associated with a series of single amino-acid substitutions in the intramembrane domain of the erythrocyte band 3 anion exchanger, AE1 [21].
• The Bcl-2 family of proteins, whose members may be anti-apoptotic or pro-apoptotic, regulates cell death by controlling this mitochondrial membrane permeability during apoptosis, but how that is achieved is unclear [22].
• Protein phosphorylation catalysed by cyclic AMP-dependent, Ca2+/calmodulin-dependent and Ca2+/diacylglycerol-dependent protein kinases is important both in the modulation of synaptic transmission and in the regulation of neuronal membrane permeability (for reviews see refs 5-7) [23].
• When administered alone, neuropeptide Y reduces the discharge of action potentials, probably by increasing the permeability of the membrane to potassium ions through the activation of a G protein; this effect is reduced in the presence of alpha2-adrenoceptor antagonists [24].
• The permeability rises when the cells are supplied with exogenous cyclic AMP or when their cyclic AMP synthesis is stimulated with choleragen or hormones; it falls when [cAMP]i is lowered by application of serum or due to increase in cell density [25].

Anatomical context of Permeability

• In vitro Ad-CFTR-infected CFPAC-1 CF epithelial cells expressed human CFTR mRNA and protein and demonstrated correction of defective cAMP-mediated Cl- permeability [26].
• Effect of cholesterol on the non-electrolyte permeability of planar lecithin membranes [27].
• Regulation of epithelial tight junction permeability by cyclic AMP [28].
• Here we show that anandamide is a potent inhibitor of gap-junction conductance and dye permeability in striatal astrocytes [29].
• These results support the contention that cholinergic-induced changes in membrane Ca2+ permeability in smooth muscle could be mediated by phosphatidate accumulation [30].

Associations of Permeability with chemical compounds

• Parthenogenetic activation with the divalent ionophore, A23187, elicits fertilization membrane elevation more rapidly than does activation by fertilization; however, the morphological and permeability changes characteristic of hardening proceed more slowly [31].
• Drugs that inhibit cytoskeletal function, such as cytochalasins B and D, colchicine, and vinblastine sulfate, are all relatively effective in preventing the TPA-induced morphological changes but not the increases in transepithelial permeability [32].
• Correction of the permeability defect in hereditary stomatocytosis by dimethyl adipimidate [33].
• These defects were reversible, as they could be normalized by plating Col6a1-/- myofibers on collagen VI or by addition of cyclosporin A (CsA), the inhibitor of mitochondrial permeability transition pore (PTP) [34].
• Glycine ethyl ester inhibits the changes in morphology, solubility, and permeability, whereas sodium sulfite inhibits only the permeability block and resistance to solubilization by mercaptans [31].

Gene context of Permeability

• Recent transgenic approaches have confirmed the profound permeability effects of VEGF (refs. 12-14), and have shown that transgenic angiopoietin-1 acts reciprocally as an anti-permeability factor when provided chronically during vessel formation, although it also profoundly affects vascular morphology when thus delivered [35].
• The N-methyl D-aspartate (NMDA) receptor subtype of glutamate-gated ion channels possesses high calcium permeability and unique voltage-dependent sensitivity to magnesium and is modulated by glycine [36].
• Vascular endothelial growth factor ([VEGF] also known as vascular permeability factor) is a potent mitogen and permeability factor, which has been suggested to play a role in embryonic and tumor angiogenesis [37].
• Our finding of cAMP-mediated Cl(-) conductance suggests that, in vivo, at least some Delta F508 CFTR can reach the plasma membrane and affect Cl(-) permeability [38].
• Microvascular endothelial water permeability, measured by a related pleural surface fluorescence method in which the airspace was filled with inert perfluorocarbon, was reduced more than 10-fold in AQP1 (-/-) vs. (+/+) mice [39].

Analytical, diagnostic and therapeutic context of Permeability

• Tracer flux studies and microelectrode measurements using intact islets of Langerhans have indicated that the initial depolarization induced by glucose is caused by a decrease in the resting membrane permeability to potassium [40].
• Adrenalectomy, but not adrenal demedullation, increased the permeability of brain tissue to the isotopically labeled macromolecule; corticosterone replacement reversed this effect [41].
• The permeability to tetraethylammonium ions was determined by injecting one cell of a pair with tetraethylammonium and monitoring its changing concentration in the prejunctional and postjunctional cells with ion-selective electrodes [42].
• Furthermore, the protective effect of high-fat enteral nutrition on inflammation-induced intestinal permeability was abrogated by vagotomy and administration of antagonists for CCK and nicotinic receptors [43].
• The contribution of peritoneal cavity lymphatic absorption to ultrafiltration kinetics and solute clearances in continuous ambulatory peritoneal dialysis was evaluated in patients with normal (group 1) and high (group 2) peritoneal permeability X area during 4-h exchanges using 2 liters 2.5% dextrose dialysis solution with 30 g added albumin [44].

References