Featherby T, Lawrence A J
Department of Pharmacology, Monash University, Clayton, Australia.
Neuroscience. 2004;127(4):949-60. doi: 10.1016/j.neuroscience.2004.06.019.
Chronic exposure to cold in rats alters the activity of locus coeruleus (LC) neurons. In this study we aimed to examine the cellular effect of cold stress on catecholamine neurons, and determine whether this is specific to the LC compared with other catecholamine cell groups. Male Sprague-Dawley rats were subjected to 21 days of isolation under ambient conditions, chronic cold exposure at 5 degrees C, or after chronic cold followed by return to ambient temperature for 7 or 14 days. In the LC, chronic cold exposure significantly reduced tyrosine hydroxylase (TH) mRNA expression by approximately 45% compared with control rats, and remained significantly reduced (approximately 36%) after return to ambient conditions for 7 days; however, expression returned to normal after 14 days' recovery. There were no significant changes in TH mRNA in the substantia nigra or ventral tegmental area. Chronic cold increased expression of alpha2A adrenoceptor mRNA in the LC (approximately 27%). There were decreases in alpha2A expression in the nucleus tractus solitarius; however, this was seen only in rats returned to ambient conditions for 7 days. Additionally, alpha2A mRNA in the caudal ventrolateral medulla (A1 region) increased following cold exposure (approximately 84%) compared with controls. Binding of [125I]iodoclonidine to alpha2-like protein increased in the olfactory bulbs but decreased in the medial amygdala following cold exposure. Collectively, these data indicate robust effects of cold on central catecholamine neurons, not necessarily specific to the LC.
大鼠长期暴露于寒冷环境会改变蓝斑（LC）神经元的活性。在本研究中，我们旨在研究冷应激对儿茶酚胺能神经元的细胞效应，并确定与其他儿茶酚胺细胞群相比，这是否对LC具有特异性。将雄性Sprague-Dawley大鼠在环境条件下隔离21天，或在5摄氏度下进行慢性冷暴露，或在慢性冷暴露后恢复到环境温度7天或14天。在LC中，与对照大鼠相比，慢性冷暴露使酪氨酸羟化酶（TH）mRNA表达显著降低约45%，在恢复到环境条件7天后仍显著降低（约36%）；然而，在恢复14天后表达恢复正常。黑质或腹侧被盖区的TH mRNA没有显著变化。慢性冷暴露使LC中的α2A肾上腺素能受体mRNA表达增加（约27%）。孤束核中的α2A表达降低；然而，这仅在恢复到环境条件7天的大鼠中可见。此外，与对照组相比，冷暴露后尾侧腹外侧延髓（A1区）的α2A mRNA增加（约84%）。冷暴露后，嗅球中[125I]碘可乐定与α2样蛋白的结合增加，而内侧杏仁核中的结合减少。总体而言，这些数据表明寒冷对中枢儿茶酚胺能神经元有显著影响，不一定对LC具有特异性。
