Bezin Laurent, Ortemann Catherine, Ogier Michaël, Astier Bernadette, Pujol Jean-François, Renaud Bernard, Lambas-Señas Laura
Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire, UMR 5123 CNRS, Université Claude Bernard Lyon I, F-69622 Villeurbanne cedex, France.
Brain Res. 2004 Dec 24;1030(1):1-10. doi: 10.1016/j.brainres.2004.07.091.
Our study was devoted to determine in freely moving rats whether the increase in tissue concentration of tyrosine hydroxylase (TH) elicited by a single administration of RU 24722 could modify the catecholaminergic reactivity of neuronal processes present in the rostrolateral part of the pericerulean area (r-lPCA) in response to tail pinch. Catecholaminergic activity was monitored by measuring in vivo the concentration of dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) using microdialysis coupled to HPLC detection. In this study, the microdialysis probe was implanted at a sufficient distance from the lateral border of rostral nucleus locus ceruleus (LC) to avoid a large contribution of the noradrenergic cell bodies in the measurements performed. We first evidenced that DOPAC measured in the r-lPCA indicated the functional state of catecholaminergic metabolism in neuronal processes (dendrites and fibers) laying in this region. We also showed that the enhancement of TH protein concentration in the r-lPCA following RU 24722 treatment supported an increased in vivo catecholaminergic metabolism in this region. Furthermore, catecholaminergic metabolism response to tail pinch was potentiated in animals with greater TH tissue concentration. Thus, our study reveals that the modulation of both TH concentration and catecholaminergic metabolism in the r-lPCA may be critical in the functioning of cells and neuronal elements present in this region, notably in adaptive responses to noxious stimuli.
我们的研究旨在确定在自由活动的大鼠中,单次给予RU 24722所引起的酪氨酸羟化酶(TH)组织浓度增加是否会改变脑桥周围区域(r-lPCA) rostrolateral部分中存在的神经元过程的儿茶酚胺能反应性,以应对尾部夹捏。通过使用与HPLC检测耦合的微透析在体内测量多巴胺代谢物3,4-二羟基苯乙酸(DOPAC)的浓度来监测儿茶酚胺能活性。在本研究中,微透析探针植入到距延髓头端蓝斑核(LC)外侧边界足够远的位置,以避免在进行的测量中去甲肾上腺素能细胞体的大量贡献。我们首先证明,在r-lPCA中测量的DOPAC表明了该区域中神经元过程(树突和纤维)中儿茶酚胺能代谢的功能状态。我们还表明,RU 24722处理后r-lPCA中TH蛋白浓度的增加支持了该区域体内儿茶酚胺能代谢的增加。此外,在TH组织浓度较高的动物中,对尾部夹捏的儿茶酚胺能代谢反应增强。因此,我们的研究表明,r-lPCA中TH浓度和儿茶酚胺能代谢的调节可能对该区域中存在的细胞和神经元成分的功能至关重要,特别是在对有害刺激的适应性反应中。