Zbuzek V, Zbuzek V K, Wu W
Neuroendocrinology. 1984 Dec;39(6):538-48. doi: 10.1159/000124035.
We studied the effect of aging on vasopressin (VP) release from isolated neurohypophyses (NH) individually superfused with synthetic medium TC 199 with Hanks' salts. The superfusion technique is described in detail. Male Fisher 344 rats 2 months (young, n = 17), 12 months (adult, n = 14) and 30 months (old, n = 17) of age were used. VP was measured by radioimmunoassay (RIA). The age-related VP release was analyzed as follows: initial traumatic release, basal release, VP release evoked by electrical stimulation (10-second trains every 20 s of matched biphasic stimuli, 0.2 ms width, 8 mA, 30 Hz), by chemical stimulation (56 mM K+) and total release for the entire superfusion period. When VP release was expressed per milligram NH, it was significantly lower under all conditions in the old rats than in the young ones. In the adult rats, traumatic, basal and total release values were similar to those of the young rats, whereas their responses to chemical and electrical stimulation were similar to those of old rats. Residual VP content expressed per whole NH was significantly higher in the old and adult rats, reflecting a larger glandular size, but when expressed per milligram NH tissue, it was low in the old rats. The percent of VP released during the entire superfusion period relative to the residual VP content was significantly lower in the old than in the young and adult rats. The magnitude of the maximal VP release exceeding the basal release, in response to electrical and chemical stimulation, was similar in young and old rats. However, in the adult rats it was significantly lower than in both the young and old following chemical stimulation. A significantly larger number of old and adult NHs exhibited a more delayed response to chemical, but not to electrical stimulation, than did the young NHs. These data demonstrate an age-related decrease in VP release in Fisher 344 rats. Since the traumatic and basal VP release in the adult rats is similar to the release in the young rats, while the stimulated release in the adult rats resembles the response of the old animals, the results suggest that an impairment of stimulated VP release occurs at an earlier stage of the aging process than does an impairment of spontaneous (traumatic and basal) release.
我们研究了衰老对从单独用含汉克斯盐的合成培养基TC 199进行灌流的离体神经垂体（NH）中释放血管加压素（VP）的影响。详细描述了灌流技术。使用了2个月龄（年轻，n = 17）、12个月龄（成年，n = 14）和30个月龄（老年，n = 17）的雄性费希尔344大鼠。通过放射免疫分析（RIA）测定VP。按以下方式分析与年龄相关的VP释放：初始创伤性释放、基础释放、电刺激（每20秒进行10秒的匹配双相刺激序列，0.2毫秒宽度，8毫安，30赫兹）、化学刺激（56毫摩尔/升钾离子）诱发的VP释放以及整个灌流期的总释放。当按每毫克NH表示VP释放时，在所有条件下老年大鼠均显著低于年轻大鼠。成年大鼠的创伤性、基础和总释放值与年轻大鼠相似，而它们对化学和电刺激的反应与老年大鼠相似。按整个NH表示的残余VP含量在老年和成年大鼠中显著更高，反映出腺体更大，但按每毫克NH组织表示时，老年大鼠中含量较低。在整个灌流期释放的VP相对于残余VP含量的百分比在老年大鼠中显著低于年轻和成年大鼠。响应电刺激和化学刺激时，超过基础释放的最大VP释放幅度在年轻和老年大鼠中相似。然而，在化学刺激后，成年大鼠中的该幅度显著低于年轻和老年大鼠。与年轻NH相比，显著更多的老年和成年NH对化学刺激（而非电刺激）表现出更延迟的反应。这些数据表明费希尔344大鼠中与年龄相关的VP释放减少。由于成年大鼠的创伤性和基础VP释放与年轻大鼠相似，而成年大鼠的刺激释放类似于老年动物的反应，结果表明刺激VP释放的损伤在衰老过程中比自发（创伤性和基础）释放的损伤发生得更早。
