Effect of chronic psychogenic stress exposure on enkephalin neuronal activity and expression in the rat hypothalamic paraventricular nucleus
Effect of chronic psychogenic stress exposure on enkephalin neuronal activity and expression in the rat hypothalamic paraventricular nucleus
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DOI：
10.1046/j.1471-4159.2000.0752200.x
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发表时间：
2000-11-01
影响因子：
4.7
通讯作者：
Drolet, G
中科院分区：
文献类型：
--
作者：
Dumont, EC;Kinkead, R;Drolet, G
本研究验证了这一假设，脑啡肽能（ENKergic）神经元室旁核的下丘脑（PVH）在心因性应激反应的激活模式是相同的，无论是在重复暴露于相同的压力（同型;固定）或一种新的压力（异型;喷气式）。大鼠被分配到急性或慢性制动应激范式（90分钟/天，分别为1天或10天）。慢性组，然后进行了额外的90分钟的会议，无论是异型或同型压力。一个单一的90分钟的应力会话（固定或空气喷射）增加PVH-ENK杂合酶（hn）RNA的表达。在慢性应激大鼠中，暴露于额外的应激会话（无论是同型还是异型）继续刺激ENK hnRNA表达。急性制动引起的背侧和腹侧内侧parvicellular，和外侧parvicellular细分的PVH的Fos免疫反应和Fos-ENK双标记细胞的数量显着增加。慢性制动引起衰减Fos反应（类似于66%），随后的制动。与此相反，慢性制动不损害ENKergic神经元激活PVH以下同型或异型应力。这些结果表明，在PVH，慢性心因性应激显着衰减Fos反应，而ENKergic神经元抵抗习惯化，主要是在腹侧神经内分泌部分的核。这表明在慢性应激暴露期间ENK效应增加。同型（固定）和异型（喷气）心因性应激源产生类似的反应，包括Fos，ENK-Fos和ENK hnRNA，在PVH的每个细分，表明无痛神经刺激的类似处理。
This study tested the hypothesis that the activation pattern of enkephalinergic (ENKergic) neurons within the paraventricular nucleus of the hypothalamus (PVH) in response to psychogenic stress is identical whether in response to repeated exposure to the same stress (homotypic; immobilization) or to a novel stress (heterotypic; air jet puff). Rats were assigned to either acute or chronic immobilization stress paradigms (90 min/day for 1 or 10 days, respectively). The chronic group was then subjected to an additional 90-min session of either heterotypic or homotypic stress. A single 90-min stress session (immobilization or air jet) increased PVH-ENK heteronuclear (hn) RNA expression. In chronically stressed rats, exposure to an additional stress session (whether homotypic or heterotypic) continued to stimulate ENK hnRNA expression. Acute immobilization caused a marked increase in the numbers of Fos-immunoreactive and Fos-ENK double-labeled cells in the dorsal and ventral medial parvicellular, and lateral parvicellular subdivisions of the PVH. Chronic immobilization caused an attenuated Fos response (similar to 66%) to subsequent immobilization. In contrast, chronic immobilization did not impair ENKergic neuron activation within the PVH following homotypic or heterotypic stress. These results indicate that within the PVH, chronic psychogenic stress markedly attenuates the Fos response, whereas ENKergic neurons resist habituation, principally within the ventral neuroendocrine portion of the nucleus. This suggests an increase in ENK effect during chronic stress exposure. Homotypic (immobilization) and heterotypic (air jet) psychogenic stressors produce similar responses, including Fos, ENK-Fos, and ENK hnRNA, within each subdivision of the PVH, suggesting similar processing for painless neurogenic stimuli.