Energy-coupling in adrenal chromaffin granules
Energy-coupling in adrenal chromaffin granules
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肾上腺嗜铬颗粒的能量耦合
DOI：
10.1016/0306-4522(76)90133-0
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发表时间：
1976
期刊：
影响因子：
3.3
通讯作者：
G. Ritchie
中科院分区：
文献类型：
--
作者：
C. Bashford;R. Casey;G. Radda;G. Ritchie
牛肾上腺髓质嗜铬颗粒的膜上含有许多与细胞能量代谢有关的活性物质。用荧光探针研究了这些活性之间的相互关系以及它们对线粒体抑制剂和解偶联剂的敏感性。该探针1-苯基-8-苯基-8-磺酸与嗜铬粒膜结合，使其荧光增强，三磷酸腺苷被嗜铬粒的三磷酸腺苷酶降解后，荧光强度进一步增加，且呈时间依赖性。这种增加是由于结合了额外的探针，而结合的探针的荧光量子产率没有变化。离子载体呋喃霉素膜上的K+扩散势改变了结合的1-苯胺基-8-磺酸的荧光量子产率。1-苯基-8-苯基-8-磺酸结合在铬粉颗粒上的荧光强度随着外加pH的降低而增强。加入线粒体解偶联剂后的荧光变化表明，嗜铬粒的内部pH较低。解偶联剂和特异性转运抑制剂利血平抑制了嗜铬粒及其膜囊泡在镁离子和三磷酸腺苷存在下对儿茶酚胺的掺入。在有镁离子和三磷酸腺苷存在的情况下，多巴胺可以刺激嗜铬粒氧化还原烟酰胺腺嘌呤二核苷酸(NADH)。线粒体抑制剂抗霉素A、寡霉素和KCN抑制嗜铬颗粒膜小泡对儿茶酚胺的掺入。它们不抑制三磷酸腺苷酶，但在有镁离子和三磷酸腺苷存在的情况下抑制多巴胺对NADH氧化的促进作用。试剂二环己基碳二亚胺抑制平行的儿茶酚胺摄取、嗜铬粒三磷酸腺苷酶活性和1-苯基-8-磺酸的相关荧光反应。根据质子在嗜铬粒内或跨膜的运动，讨论了嗜铬粒内的能量产生和消耗过程与不同类型的抑制剂作用部位的关系。
The membrane of bovine adrenomedullary chromaffin granules contains a number of activities associated with cellular energy metabolism. The interrelationship of these activities and their sensitivity to mitochondrial inhibitors and uncouplers were explored using a fluorescent probe. The probe, 1-anilinonaphthalene-8-sulphonic acid, binds to chromaffin granule membranes resulting in an enhancement of its fluorescence.Hydrolysis of adenosine triphosphate by the adenosine triphosphatase of chromaffin granules produces a further time dependent increase in the fluorescence of the probe. This increase is caused by the binding of additional probe with no change in the fluorescence quantum yield of bound probe. A K+diffusion potential across the membrane of chromaffin granules induced by the ionophore valinomycin changes the fluorescence quantum yield of bound 1-anilinonaphthalene-8-sulphonic acid. The fluorescence of 1-anilinonaphthalene-8-sulphonic acid bound to chromaffin granules increases as the external pH is lowered. The change in fluorescence on addition of a mitochondrial uncoupling agent suggests that the internal pH of chromaffin granules is low.The incorporation of catecholamines by chromaffin granules and their membrane vesicles in the presence of Mg2+and adenosine triphosphate is inhibited by uncouplers and the specific transport inhibitor, reserpine. The oxidation of reduced nicotinamide adenine dinucleotide (NADH) by chromaffin granules is stimulated by dopamine in the presence of Mg2+and adenosine triphosphate. Mitochondrial inhibitors antimycin A, oligomycin and KCN inhibit catecholamine incorporation by membrane vesicles prepared from chromaffin granules. They do not inhibit the adenosine triphosphatase but do inhibit the enhancement of NADH oxidation induced by dopamine in the presence of Mg2+and adenosine triphosphate. The reagent dicyclohexylcarbodiimide inhibits in parallel catecholamine uptake, the activity of chromaffin granule adenosine triphosphatase and the associated fluorescence response of 1-anilinonaphthalene-8-sulphonic acid.The relationships between the energy producing and the energy consuming processes in chromaffin granules and the sites of action of different types of inhibitors are discussed in terms of proton movements within or across the membrane of chromaffin granules.