Gavrilovic Ljubica, Spasojevic Natasa, Tanic Nikola, Dronjak Sladjana
Institute of Nuclear of Sciences 'Vinca', Laboratory of Molecular Biology and Endocrinology, 11000 Belgrade, Serbia.
Neuro Endocrinol Lett. 2008 Dec;29(6):1015-20.
Isolation of adult animals represents a form of psychsocial stress that produces sympatho-adrenomedullar activation. The aim of this work was to investigate the changes in gene expression and protein levels of catecholamine biosynthetic enzymes: tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in the adrenal medulla of naive control and chronically (12 weeks) socially isolated adult Wistar rat males and the response of these animals to additional immobilization stress (2 h).
TH, DBH and PNMT mRNA levels were quantified by quantitative real-time RT-PCR (qRT-PCR). TH, DBH and PNMT immunoproteins were assayed by Western Blot.
In chronically isolated rats, gene expression levels of catecholamine biosynthetic enzymes in the adrenal medulla were decreased, but only TH mRNA was significantly decreased. However, protein levels of TH, DBH and PNMT of these animals were elevated by 55%, 20% and 18%, respectively, in relation to the corresponding control. Naive control and chronically socially isolated rats exposed to additional 2-h-immobilization showed increased gene expression of the examined enzymes, the increase being greater in socially isolated rats as compared to the controls. Additional immobilization of naive controls did not affect TH, DBH and PNMT protein levels. In contrast, this stress produced increased TH, DBH and PNMT protein levels in long-term socially isolated rats.
We can conclude that psychosocial stress expressed a differential influence on gene expression and protein levels of catecholamine biosynthetic enzymes in the adrenal medulla of adult rats. The results indicate a possible adaptation of catecholamine-synthesizing system at the level of TH gene expression in adrenal medulla of chronically isolated animals.
成年动物的隔离是一种社会心理应激形式，可引起交感 - 肾上腺髓质激活。本研究旨在调查初次对照和长期（12周）社会隔离的成年雄性Wistar大鼠肾上腺髓质中儿茶酚胺生物合成酶：酪氨酸羟化酶（TH）、多巴胺β-羟化酶（DBH）和苯乙醇胺N-甲基转移酶（PNMT）的基因表达和蛋白质水平变化，以及这些动物对额外固定应激（2小时）的反应。
通过定量实时RT-PCR（qRT-PCR）定量TH、DBH和PNMT的mRNA水平。通过蛋白质免疫印迹法检测TH、DBH和PNMT免疫蛋白。
在长期隔离的大鼠中，肾上腺髓质中儿茶酚胺生物合成酶的基因表达水平降低，但只有TH mRNA显著降低。然而，与相应对照相比，这些动物的TH、DBH和PNMT蛋白质水平分别升高了55%、20%和18%。初次对照和长期社会隔离的大鼠在额外接受2小时固定应激后，所检测酶的基因表达增加，且社会隔离大鼠的增加幅度大于对照。初次对照的额外固定应激不影响TH、DBH和PNMT蛋白质水平。相反，这种应激使长期社会隔离大鼠的TH、DBH和PNMT蛋白质水平升高。
我们可以得出结论，社会心理应激对成年大鼠肾上腺髓质中儿茶酚胺生物合成酶的基因表达和蛋白质水平有不同影响。结果表明，在长期隔离动物肾上腺髓质的TH基因表达水平上，儿茶酚胺合成系统可能存在适应性变化。
