Haxhiu M A, Yung K, Erokwu B, Cherniack N S
Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
Respir Physiol. 1996 Aug;105(1-2):35-45. doi: 10.1016/0034-5687(96)00034-5.
In these studies we examined c-fos expression in catecholaminergic neurons following exposure of unanesthetized rats to hypercapnic stress. Breathing a gas mixture with elevated CO2 (15% CO2, 21% O2 and 64% N2, or 15% CO2 balance O2) for 60 min, induced activation of the c-fos gene in widespread regions of the CNS, as indicated by the expression of Fos-like immunoreactive protein (Fos). Similar results were obtained in carotid body denervated animals. Colocalization studies of tyrosine hydroxylase (TH) and Fos protein revealed that in the brainstem, 73 to 85% of noradrenaline-containing cells expressed Fos immunoreactivity. Double-labeled neurons were found in the ventrolateral medullary reticular formation (A1 noradrenaline cells), in the dorsal aspect of medulla oblongata (A2 noradrenaline cells), in the ventrolateral pons (A5 noradrenaline cells), and in the locus coeruleus (A6 noradrenaline cells). However, over 90% of TH-immunoreactive neurons in the mesencephalon and diencephalon (dopaminergic cells) did not express Fos-like immunoreactivity in response to CO2. These results indicate that the brainstem noradrenaline-containing neurons are part of the neuronal networks that react to hypercapnic exposure.
在这些研究中，我们检测了未麻醉大鼠暴露于高碳酸血症应激后，儿茶酚胺能神经元中c-fos的表达。呼吸含高浓度二氧化碳的混合气体（15%二氧化碳、21%氧气和64%氮气，或15%二氧化碳，其余为氧气）60分钟，可诱导中枢神经系统广泛区域的c-fos基因激活，这通过Fos样免疫反应蛋白（Fos）的表达得以体现。在颈动脉体去神经支配的动物中也获得了类似结果。酪氨酸羟化酶（TH）和Fos蛋白的共定位研究表明，在脑干中，73%至85%含去甲肾上腺素的细胞表达Fos免疫反应性。在腹外侧髓质网状结构（A1去甲肾上腺素能细胞）、延髓背侧（A2去甲肾上腺素能细胞）、脑桥腹外侧（A5去甲肾上腺素能细胞）和蓝斑（A6去甲肾上腺素能细胞）中发现了双标记神经元。然而，中脑和间脑（多巴胺能细胞）中超过90%的TH免疫反应性神经元对二氧化碳无Fos样免疫反应性表达。这些结果表明，脑干中含去甲肾上腺素的神经元是对高碳酸血症暴露产生反应的神经网络的一部分。
