Smith M A, Brady L S, Glowa J, Gold P W, Herkenham M
Section on Functional Neuroanatomy, NIMH, Bethesda, MD 20892.
Brain Res. 1991 Mar 22;544(1):26-32. doi: 10.1016/0006-8993(91)90881-u.
The locus ceruleus-norepinephrine system is one of the principal effectors of the stress response. Acute stress induces norepinephrine synthesis and release, and noradrenergic cells compensate by increasing the activity of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis. Here we use in situ hybridization histochemistry to show the effects of acute and chronic intermittent stress on the expression of tyrosine hydroxylase mRNA in the rat locus ceruleus. Restraint stress increased tyrosine hydroxylase mRNA in the locus ceruleus but not in dopaminergic nuclei such as the substantia nigra or ventral tegmental area. One hour of footshock or restraint caused a rapid increase in locus ceruleus tyrosine hydroxylase mRNA which returned to basal levels within 24 h. Chronic intermittent stress (1 hour of restraint or footshock per day for 14 days) produced no change in tyrosine hydroxylase mRNA. Neither adrenalectomy nor dexamethasone replacement significantly affected mRNA expression. These findings indicate that acute stress can increase the expression of tyrosine hydroxylase mRNA in the locus ceruleus but that adaptation occurs to repeated stress, and that the expression of tyrosine hydroxylase mRNA in the locus ceruleus is independent of direct glucocorticoid modulation.
蓝斑 - 去甲肾上腺素系统是应激反应的主要效应器之一。急性应激会诱导去甲肾上腺素的合成与释放，去甲肾上腺素能细胞通过增加酪氨酸羟化酶（儿茶酚胺合成中的限速酶）的活性来进行代偿。在此，我们运用原位杂交组织化学技术来展示急性和慢性间歇性应激对大鼠蓝斑中酪氨酸羟化酶mRNA表达的影响。束缚应激增加了蓝斑中酪氨酸羟化酶mRNA的表达，但在诸如黑质或腹侧被盖区等多巴胺能核团中却未增加。1小时的足部电击或束缚导致蓝斑中酪氨酸羟化酶mRNA迅速增加，该水平在24小时内恢复至基础水平。慢性间歇性应激（每天1小时束缚或足部电击，持续14天）并未使酪氨酸羟化酶mRNA发生变化。肾上腺切除术和地塞米松替代治疗均未显著影响mRNA表达。这些发现表明，急性应激可增加蓝斑中酪氨酸羟化酶mRNA的表达，但对反复应激会产生适应性变化，并且蓝斑中酪氨酸羟化酶mRNA的表达独立于直接的糖皮质激素调节。
