Mateo Y, Meana J J
Department of Pharmacology, University of the Basque Country, Euskal Herriko Unibersitatea, Leioa, Bizkaia, Spain.
Eur J Pharmacol. 1999 Aug 20;379(1):53-7. doi: 10.1016/s0014-2999(99)00488-4.
The regulation of extracellular noradrenaline levels in the cingulate cortex by somatodendritic alpha2-adrenoceptors located in the locus coeruleus was evaluated in the rat by using dual-probe microdialysis. The concentration of noradrenaline in the cingulate cortex was decreased (37%-40%) by administration into the locus coeruleus (1microM) of the agonists clonidine and UK14304 (bromoxidine), whereas it was increased by similar administration of the nonselective antagonist RX821002 (2-methoxyidazoxan) (+ 103%) and the selective alpha2A-adrenoceptor antagonist BRL44408 (2-[2H-(1-methyl-1,3-dihydroisoindole)methyl]-4,5-dihydroimidaz ole) (+ 148%). The selective alpha2B/C-adrenoceptor antagonist ARC239 (2-[2[4-(o-methoxyphenyl)piperazin-1-yl]ethyl]-4,4-dimethyl-1,3-(2 H,4H)-isoquinolimedione) did not induce changes. In the presence of BRL44408, the effects of clonidine and UK14304 were abolished, but they were not modified in the presence of ARC239. The data demonstrate that noradrenaline release in terminal areas is tonically modulated by somatodendritic alpha2A-adrenoceptors.
通过使用双探针微透析技术，在大鼠中评估了位于蓝斑的树突体α2-肾上腺素能受体对扣带回皮质细胞外去甲肾上腺素水平的调节作用。向蓝斑注射激动剂可乐定和UK14304（溴莫尼定，1μM），扣带回皮质中的去甲肾上腺素浓度降低（37%-40%），而注射非选择性拮抗剂RX821002（2-甲氧基咪唑克生）（+103%）和选择性α2A-肾上腺素能受体拮抗剂BRL44408（2-[2H-(1-甲基-1,3-二氢异吲哚)甲基]-4,5-二氢咪唑）（+148%）则使其浓度升高。选择性α2B/C-肾上腺素能受体拮抗剂ARC239（2-[2[4-(邻甲氧基苯基)哌嗪-1-基]乙基]-4,4-二甲基-1,3-(2H,4H)-异喹啉二酮）未引起变化。在存在BRL44408的情况下，可乐定和UK14304的作用被消除，但在存在ARC239的情况下其作用未改变。这些数据表明，树突体α2A-肾上腺素能受体对终末区域去甲肾上腺素的释放具有紧张性调节作用。
