Henseling M, Eckert E, Trendelenburg U
Naunyn Schmiedebergs Arch Pharmacol. 1976;292(3):205-17. doi: 10.1007/BF00517381.
Rabbit aortic strips (nerve-free, reserpine-pretreated or normal) whose noradrenaline-metabolizing enzymes were inhibited (by in vitro treatment with 0.5 mM pargyline for 30 min and by the presence of 0.1 mM U-0521) were exposed to 1.18 muM 3H-(+/-)noradrenaline for 30 min (in most experiments). At the end of the incubation some strips were used for analysis of radioactivity (i.e., of noradrenaline and its metabolites), while for others the efflux of radioactivity was determined during 240 min of wash out with amine-free solution. An estimate of the original distribution of the amine into the various extraneuronal and neuronal compartments of the tissue was obtained by compartmental analysis of the efflux curves. 1. Extracellular amine distributes into "compartment I + II" (characterized by a half time for efflux of less than 1 min); compartment size and half time for efflux were similar to those obtained for 14C-sorbitol. 2. The extraneuronal accumulation of noradrenaline is a quickly equilibrating process which involves compartments III and IV (with half times for efflux of 3 and 11 min, respectively). Compartment IV represents not only extraneuronally but also neuronally distributed noradrenaline (see below, 4). 3. The neuronal accumulation of noradrenaline is a slowly equilibrating process which can be subdivided into axoplasmic and vesicular accumulation. 4. The axoplasmic accumulation of noradrenaline is associated with compartments IV and V (the latter characterized by a half time for efflux of 95 min). The half time of the efflux from compartment V was independent of the original filling of this compartment (the degree of filling having been varied by changes in the duration and the amine concentration of the incubation). 5. The vesicular accumulation of noradrenaline resulted in the appearance of a "bound fraction" (i.e., of amine not participating in the efflux determined during 240 min of wash out) and in an increase in the half time of the efflux from compartment V. 6. The results support the view that the rate of relaxation (of strips initially exposed to noradrenaline and then washed out) is affected by the efflux of unchanged amine from extraneuronal and neuronal stores.
将兔主动脉条（无神经、经利血平预处理或正常的）的去甲肾上腺素代谢酶抑制（通过在体外以0.5 mM优降宁处理30分钟以及存在0.1 mM U - 0521），使其暴露于1.18 μM 3H-(±)去甲肾上腺素30分钟（在大多数实验中）。孵育结束时，一些主动脉条用于放射性分析（即去甲肾上腺素及其代谢产物的分析），而其他的则在用无胺溶液洗脱240分钟期间测定放射性流出量。通过对流出曲线进行房室分析，获得了胺在组织的各种细胞外和细胞内房室中的原始分布估计。1. 细胞外胺分布到“房室I + II”（其特征为流出半衰期小于1分钟）；房室大小和流出半衰期与用14C - 山梨醇获得的相似。2. 去甲肾上腺素的细胞外蓄积是一个快速平衡过程，涉及房室III和IV（流出半衰期分别为3分钟和11分钟）。房室IV不仅代表细胞外分布的去甲肾上腺素，也代表细胞内分布的去甲肾上腺素（见下文4）。3. 去甲肾上腺素的细胞内蓄积是一个缓慢平衡过程，可细分为轴浆蓄积和囊泡蓄积。4. 去甲肾上腺素的轴浆蓄积与房室IV和V相关（后者特征为流出半衰期为95分钟）。从房室V流出的半衰期与该房室的初始填充无关（通过改变孵育持续时间和胺浓度来改变填充程度）。5. 去甲肾上腺素的囊泡蓄积导致出现“结合部分”（即不参与在240分钟洗脱期间测定的流出的胺），并使从房室V流出的半衰期增加。6. 结果支持这样的观点，即（最初暴露于去甲肾上腺素然后洗脱的主动脉条的）松弛速率受来自细胞外和细胞内储存的未改变胺的流出影响。
