The effect of age on presynaptic alpha 2 adrenoceptor autoregulation of norepinephrine release.
The effect of age on presynaptic alpha 2 adrenoceptor autoregulation of norepinephrine release.
复制标题
年龄对突触前 α2 肾上腺素受体去甲肾上腺素释放自动调节的影响。
DOI：
10.1093/geronj/44.3.b59
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Roberts,J
中科院分区：
文献类型：
--
作者：
Daly,RN;Goldberg,PB;Roberts,J
在6、12和24月龄的雄性fischer 344大鼠离体心脏中研究了年龄对突触前α 2肾上腺素受体介导的去甲肾上腺素（NE）释放调节的影响。分别向灌注液中加入钴（10 - 6 M）和间苯二甲酸（10 - 5 M），并结合使用，以分别阻断神经元和神经元的摄取机制。在任何给定的神经刺激频率下，流出物中的ne溢出量随着年龄的增加而显着降低。仅在12月龄和24月龄动物的心脏制备物中，美坦利增加NE溢出。育亨宾是一种选择性α 2肾上腺素受体拮抗剂，浓度为10− 6 M和3 × 10− 6 M时，仅在6个月大动物心脏的灌注流出液中显著增加NE溢出量。这些结果表明，神经元的摄取机制随着年龄的增长而增加，突触前α 2肾上腺素受体介导的NE的自动调节随着年龄的增长而减少。这一发现至少可以部分解释肾上腺素对心脏的控制能力随年龄增长而下降的原因。
The effect of age on presynaptic alpha2adrenoceptor-mediated regulation of norepinephrine (NE) release was studied in hearts isolated from male fischer 344 rats 6-, 12-and 24-months of age. Cocaine (10−6M) and metanephrine (10−5M) were added to the perfusion fluid separately and in combination to block neuronal and extraneuronal uptake mechanisms, respectively. The amount of ne overflow in the effluent was significantly lower with increasing age at any given frequency of nerve stimulation. Metanephrine increased NE overflow in heart preparations of 12-and 24-month-old animals only. Yohimbine, a selective alpha2adrenoceptor antagonist, at concentrations of 10−6M and 3 × 10−6M significantly increased the amount of NE overflow only in the perfusion effluent of hearts isolated from 6-month-old animals. These results suggest that extraneuronal uptake mechanisms increase with age and that presynaptic alpha2adrenoceptor-mediated autoregulation of NE decreases with age. The findings could account, at least in part, for the decrease in adrenergic control of the heart shown to occur with age.