GREATLY EXTENDED VIABILITY OF RAT-BRAIN STORAGE-VESICLES IN AN INTRACELLULAR MEDIUM BASED UPON A NON-PERMEANT POLYANION
GREATLY EXTENDED VIABILITY OF RAT-BRAIN STORAGE-VESICLES IN AN INTRACELLULAR MEDIUM BASED UPON A NON-PERMEANT POLYANION
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DOI:
10.1016/0024-3205(81)90608-1
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发表时间:
1981-01-01
期刊:
影响因子:
6.1
通讯作者:
RUTH, JA
中科院分区:
文献类型:
--
作者:
DISBROW, JK;RUTH, JA
The MgATP-stimulated accumulation of (-)-3H-norepinephrine (NE) by rat brain neuronal storage vesicles was characterized in a new medium based upon polyacrylic acid (avg. MW 5000). The medium allows careful regulation of K+ concentration (140 mM), has a large buffer capacity and is non-permeant to membranes. Light scattering measurements confirmed the osmotic stability of vesicles suspended in this medium. Vesicular accumulation of (-)-3H-NE (Km 1 .times. 10-6 M) in this system (37.degree.) was examined under saturating (10-5 M) and non-saturating (2 .times. 10-7 M) concentrations of NE. At 10-5 M NE, uptake saturated at 5 min and remained stable for periods up to 1 h, with maximal uptake levels (pmol/mg protein) of 15.7 .+-. 0.30 (37.degree.), 3.0 .+-. 0.49 (0.degree.), 4.4 .+-. 0.22 (reserpine-pretreated in vivo) and 6.0 .+-. 0.79 (without MgATP). At 2 .times. 10-7 M NE uptake was biphasic with maximal uptake levels (pmol/mg protein) of 4.04 .+-. 0.14 (37.degree.), 0.19 .+-. 0.01 (0.degree.), 0.95 .+-. 0.06 (reserpine) and 0.83 .+-. 0.08 (without MgATP). Vesicle preparations refrigerated in this medium for 24 h displayed properties similar to those measured acutely (NE = 2.2 .times. 10-7 M).