Restraint stress decreases the neurosecretory activity of tuberoinfundibular dopaminergic neurons in young but not in aged female rats.
Restraint stress decreases the neurosecretory activity of tuberoinfundibular dopaminergic neurons in young but not in aged female rats.
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束缚应激会降低年轻雌性大鼠结节漏斗部多巴胺能神经元的神经分泌活性，但不会降低老年雌性大鼠的神经分泌活性。
DOI：
10.1159/000124755
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发表时间：
1987
影响因子：
4.1
通讯作者：
Riegle,GD
中科院分区：
文献类型：
--
作者：
Demarest,KT;Moore,KE;Riegle,GD
老年大鼠垂体后叶多巴胺（DA）神经元对催乳素分泌的调节发生改变：血清中催乳素浓度升高，垂体后叶多巴胺神经元活性降低。在年轻的雌性大鼠中，短暂的应激会降低结节底叶DA神经分泌活性，增加催乳素的分泌。本研究的目的是确定老年雌性大鼠下颌结节基底DA神经元对抑制应激的反应性是否发生改变。这些神经元的活性是通过它们在中央隆起末端的DA合成速率来估计的，在给予脱羧酶抑制剂后，通过二羟基苯丙氨酸（DOPA）的积累速率来测量。30分钟的约束应激增加了幼龄（3个月）和老年（26个月）持续发情大鼠的血清催乳素浓度，但降低了多巴在正中隆起的积累速率。抑制还降低了中年大鼠（14个月）中隆起的多巴积累率，而这与大鼠是否表现出正常的卵巢周期（在发情期当天测量）或处于持续发情期无关。这表明卵巢周期本身的丧失与结节眼底DA神经元对抑制应激反应的年龄相关变化无关。为了确定老年大鼠结节性眼底DA神经元对应激反应的缺乏是否与这些神经元基础活性的降低有关，我们在给予氟哌啶醇预处理的大鼠中测定了结节性眼底DA神经元对30分钟抑制的反应。氟哌啶醇增加了血清催乳素水平，从而增加了年轻和年老大鼠的结节底叶DA神经元的活性，但抑制应激只降低了年轻大鼠的多巴积累率。这些结果表明，应激对老年大鼠垂体后叶DA神经元的抑制作用受损，并表明介导这种反应的抑制性神经元机制随着雌性大鼠年龄的增长而被破坏。
The regulation of prolactin secretion by tuberoinfundibular dopamine (DA) neurons appears to be altered in the aged rat: the concentration of prolactin in the serum increases and the activity of the tuberoinfundibular DA neurons decreases. In the young female rat a brief period of stress reduces the tuberoinfundibular DA neurosecretory activity and increases the secretion of prolactin. The purpose of the present study was to determine if the responsiveness of tuberoinfundibular DA neurons to restraint stress is altered in the aged female rat. The activity of these neurons was estimated from the rate of DA synthesis in their terminals in the median eminence, as measured by the rate of accumulation of dihydroxy-phenylalanine (DOPA) after the administration of a decarboxylase inhibitor. Thirty minutes of restraint stress increased serum prolactin concentrations in both young (3 months) and aged (26 months) constant estrous rats, but reduced the rate of DOPA accumulation in the median eminence of only the young rats. Restraint also decreased the rate of DOPA accumulation in the median eminence of intermediate-aged rats (14 months) independently of whether the rats were exhibiting normal ovarian cycles (measured on the day of estrus) or were in a constant estrus. This suggests that the loss of ovarian cyclicity per se is not associated with the age-related change in the response of tuberoinfundibular DA neurons to restraint stress. To determine if the lack of response of tuberoinfundibular DA neurons to stress is related to the reduced basal activity of these neurons in the aged rat, the response of tuberoinfundibular DA neurons to 30 min of restraint was determined in rats that were pretreated with haloperidol. Haloperidol increased serum prolactin levels and consequently the tuberoinfundibular DA neuronal activity in both young and aged rats, but restraint stress reduced the rate of DOPA accumulation only in the young rats. These results reveal that the inhibition of tuberoinfundibular DA neurons by stress is impaired in the aged rat and suggest that the inhibitory neuronal mechanisms that mediate this response become disrupted as the female rat ages.
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
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