Sara S J, Devauges V, Biegon A
Institut des Neurosciences, CNRS Université Pierre & Marie Curie, Paris, France.
Behav Brain Res. 1993 Oct 21;57(1):101-4. doi: 10.1016/0166-4328(93)90065-x.
Maudsley rats, selectively inbred for emotionality for over sixty generations, differ in reactivity to stress, both at the peripheral level and within the central noradrenergic system. The present experiments examine to what extent these central differences might be due to differences in the inhibitory processes mediated by alpha 2 autoreceptors within the locus coeruleus. Maudsley reactive rats (MRs), the strain which showed a much higher central noradrenergic response to immobilisation stress, required higher doses of the alpha 2 receptor agonist, clonidine, to induce behavioral sedation than the Maudsley non-reactive rats (MNRA). Autoradiographic studies showed a significantly higher level of binding of 125iodeclonidine in the locus coeruleus of the MNRAs compared to the MRs, indicating that the former had more alpha 2 receptors and/or these receptors had a greater affinity for the agonist. Thus autoinhibitory processes within the locus coeruleus are different in the two strains, which could account for the differences in reactivity to stress seen in the biochemical and behavioral studies.
经过六十多代选择性近亲繁殖培育出的莫兹利大鼠，在对外周应激和中枢去甲肾上腺素能系统的反应性方面存在差异。本实验旨在研究这些中枢差异在多大程度上可能归因于蓝斑内α2自受体介导的抑制过程的差异。莫兹利反应性大鼠（MRs），即对固定应激表现出更高中枢去甲肾上腺素能反应的品系，与莫兹利非反应性大鼠（MNRA）相比，需要更高剂量的α2受体激动剂可乐定来诱导行为镇静。放射自显影研究表明，与MRs相比，MNRA蓝斑中125碘可乐定的结合水平显著更高，这表明前者具有更多的α2受体和/或这些受体对激动剂具有更高的亲和力。因此，蓝斑内的自身抑制过程在这两个品系中是不同的，这可以解释在生化和行为研究中观察到的对应激反应性的差异。
