Flügge G, Jöhren O, Fuchs E
German Primate Center, Göttingen.
Brain Res. 1992 Nov 27;597(1):131-7. doi: 10.1016/0006-8993(92)91514-f.
The aim of the present study was to investigate the influence of social status on central nervous alpha 2-adrenoceptors. Using the specific alpha 2-adrenoceptor antagonist [3H]rauwolscine, binding sites in the brains of dominant and subordinate male tree shrews were quantified by in vitro autoradiography. In 5 of the 14 brain structures investigated, subordinates had significantly lower numbers of binding sites than dominants. These structures were the solitary tract nucleus, the dorsal motor nucleus of the vagus, the periaqueductal gray, the perifornical region of the hypothalamus and the medial nucleus of the amygdala. These brain areas are all intimately involved in the regulation of autonomic functions and of emotional behavior. Also the affinities for [3H]rauwolscine differed between the groups. In 3 nuclei, the solitary tract nucleus, the periaqueductal gray and the medial nucleus of the amygdala, dominants had significantly higher Kd-values than subordinates. This demonstrates the presence of low affinity binding sites in dominants which do not exist in subordinates. It is suggested that the low number of [3H]rauwolscine binding sites in subordinates results from down-regulation of alpha 2-adrenoceptors by high levels of noradrenaline and/or adrenaline. The disappearance of low affinity [3H]rauwolscine binding sites may play an important role in the etiology of psychosocial stress.
本研究的目的是调查社会地位对中枢神经α2-肾上腺素能受体的影响。使用特异性α2-肾上腺素能受体拮抗剂[3H]萝芙木碱，通过体外放射自显影法对优势和从属雄性树鼩大脑中的结合位点进行定量。在所研究的14个脑结构中的5个结构中，从属树鼩的结合位点数显著低于优势树鼩。这些结构是孤束核、迷走神经背运动核、导水管周围灰质、下丘脑穹窿周区和杏仁核内侧核。这些脑区均密切参与自主功能和情绪行为的调节。而且两组对[3H]萝芙木碱的亲和力也有所不同。在3个核团，即孤束核、导水管周围灰质和杏仁核内侧核中，优势树鼩的解离常数（Kd）值显著高于从属树鼩。这表明优势树鼩中存在低亲和力结合位点，而从属树鼩中不存在。研究表明，从属树鼩中[3H]萝芙木碱结合位点数少是由于高水平的去甲肾上腺素和/或肾上腺素导致α2-肾上腺素能受体下调所致。低亲和力[3H]萝芙木碱结合位点的消失可能在心理社会应激的病因学中起重要作用。
