Membranes, isolated effect

Local anesthetics produce anesthesia by blocking nerve impulse conduction in sensory, as well as motor nerve, fibers. Nerve impulses are initiated by membrane depolarization, effected by the opening of a sodium ion channel and an influx of sodium ions. Local anesthetics act by inhibiting the channel s opening they bind to a receptor located in the channel s interior. The degree of blockage on an isolated nerve depends not only on the amount of dmg, but also on the rate of nerve stimulation (153—156). 

Changes in EFA status affect the activity of several membrane-associated enzymes and proteins 68-71 Reduced adenyl cyclase activity occurred in EFA-deficient animals,72 while in animals supplemented with n-6 or n-3 fatty acids, increased adenyl cyclase activity was seen in cardiac membranes.73,74 However, the opposite effect has been reported in other membranes, possibly reflecting differences in initial fatty acid composition.75 n-3 PUFAs have been shown to activate membrane Ca-ATPase and inhibit Na, K-ATPase in isolated basolateral membranes from rat duodenal enterocytes76 and inhibit both Ca-ATPase and Na,K-ATPase activity in synaptosomal membranes isolated from rat cerebral cortex.77 EFAs have the ability to modify neuronal Ca-ATPase activity... 

Corredig, M., Dalgleish, D.G. 1998. Effect of heating of cream on the properties of milk fat globule membrane isolates. J. Agric. Food Chem. 46, 2533-2540. 

We suggested that addition of a saturated fatty-acid tail (buoy) that incorporates in the antioxidant molecule membrane may make the membrane more rigid and thus contribute to the therapeutic effect of ichfan. As is seen from Table 1, after introduction of the compoimd to mice, the microviscosity of the membrane near-surface sites studied by the method of EPR spin probes either changes insignificantly or increases the latter is a desirable effeet. It should be emphasized particularly for membranes isolated from a coarse fraction of synaptosomes because AD is associated mostly with damages of nerve fibers. 

Sodium uptake assay. Assays using mouse brain synaptosomes were performed as described previously (6., ), except that insecticides were introduced to resuspended synaptosomes in 0.2-0.4 yl of ethanol rather than as a residue in the incubation tube. This amount of ethanol improved the delivery of insecticides, thereby increasing the reproducibility of the assay, and had no measurable effect on veratridine-dependent sodium channel activation. These methods were also used for assays with fish brain membranes, except that all buffers were augmented with sucrose to give osmolarities equivalent to the 0 7 M sucrose used for membrane isolation. 

Hum. Crude material isolated from the mycelium was relatively low in proteases and in high molecular weight impurities. Supernatant provided much more raw material initially (up to 300 yg/ml by HPLC) but this F-II was high in protease activity and was contaminated with huge amounts of proteinaceous material from the medium. The experiences learned in the development of process II, namely the ability of hydroxylapatite to remove very similar impurities and the success of durapore membranes to effectively remove large amounts of high molecular weight contaminants, spurred further work on a supernatant process. 

Liver cell membranes isolated and incubated in buffered solutions of BSP (C36), bound 160 d=2 fig BSP per milligram of membrane protein. BSP binding was maximal at 500 /u.g of BSP per milliliter of incubation mixture and at pH values below 7. Maximum binding was completed in 3 minutes and unaffected by the addition of K+, Ca +, or CL. Tauro-cholate, bilirubin, and uranin had no effect on binding, but flavaspidic acid (see Section 7.3), iodipamide methylglucamine (see Section 7.1), and indocyanine green were inhibitory. 

During activation of postganglionic sympathetic nerves there is an exocytotlc release of norepinephrine which is dependent upon the movement of calcium across the neural cell membrane. The effects of CEB on stimulus-secretion coupling in S3nnpathetlc nerves has been studied in several different preparations. Verapamil does not affect the neural release of norepinephrine in either Isolated cat heart or in the pithed rat. In the latter model nifedipine blunted increases in blood pressure due to activation of sympathetic nerves but did not affect cardiovascular responses to exogenous norepinephrine suggesting a prejunctional site of inhibition. 

Fig. 1. Effect of cerulenin on B. subtilis 168. O.D. at 590 nm (% of a control culture without cerulenin) specific ATPase activity of membranes isolated from cells grown in the presence of cerulenin (in % of the control). 

Schneider H 1955 Ontogeny of lemon tree bark. Am J Bot 42 893-905 Schonherr J 1976 Water permeability of isolated cuticular membranes the effect of cuticular waxes on diffusion of water. Planta 131 159-164... 

Brauker, 1. et al.. Neovascularization of immuno-isolation membranes the effect of membrane architecture and encapsulated tissue. Cell Transplant., 1,163,1992. 

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