Chu T C, Socci R R, Ogidigben M J, Potter D E
Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, USA.
J Ocul Pharmacol Ther. 1997 Dec;13(6):489-96. doi: 10.1089/jop.1997.13.489.
In rabbit's aqueous humor, norepinephrine, epinephrine, dopamine and serotonin were detected simultaneously by a high performance liquid chromatography with electrochemical detection. Furthermore, the changes in catecholamine levels in aqueous humor were evaluated after topical application of moxonidine, an imidazoline1/alpha 2 receptor agonist, in the presence and absence of efaroxan. The level of norepinephrine in aqueous humor was reduced by moxonidine treatment. However, under the same set of conditions, there were no significant changes in the levels of dopamine, epinephrine or serotonin. Pretreatment with efaroxan antagonized moxonidine-induced suppression of norepinephrine levels. In other in vivo experiments, moxonidine caused a decrease in intraocular pressure which was antagonized by pretreatment with efaroxan. In the superior cervical ganglion preparation, norepinephrine release was increased 5-fold by the presence of a high K+ medium. The K(+)-evoked norepinephrine secretion was reduced by 55% by moxonidine. Pretreatment with efaroxan blocked the moxonidine-induced inhibition of norepinephrine release. It is concluded that inhibition of norepinephrine release from the superior cervical ganglion and suppression of aqueous norepinephrine levels contribute to the moxonidine-induced lowering of intraocular pressure. Moreover, the antagonism of moxonidine's in vivo and in vitro effects by efaroxan suggests the involvement of imidazoline1 receptors, but does not preclude activity on alpha 2 adrenoceptors.
采用高效液相色谱-电化学检测法同时检测了兔房水中的去甲肾上腺素、肾上腺素、多巴胺和5-羟色胺。此外，在有和没有依酚氯铵的情况下，局部应用莫索尼定（一种咪唑啉1/α2受体激动剂）后，评估了房水中儿茶酚胺水平的变化。莫索尼定处理可降低房水中去甲肾上腺素的水平。然而，在相同条件下，多巴胺、肾上腺素或5-羟色胺的水平没有显著变化。依酚氯铵预处理可拮抗莫索尼定诱导的去甲肾上腺素水平抑制。在其他体内实验中，莫索尼定可导致眼压降低，而依酚氯铵预处理可拮抗这种降低。在颈上神经节制备实验中，高钾培养基可使去甲肾上腺素释放增加5倍。莫索尼定可使钾离子诱发的去甲肾上腺素分泌减少55%。依酚氯铵预处理可阻断莫索尼定诱导的去甲肾上腺素释放抑制。得出的结论是，抑制颈上神经节去甲肾上腺素释放和抑制房水去甲肾上腺素水平有助于莫索尼定诱导的眼压降低。此外，依酚氯铵对莫索尼定体内和体外作用的拮抗作用表明咪唑啉1受体参与其中，但不排除对α2肾上腺素能受体有活性。
