Glue P, Wilson S, Campling G M, Knightly M, Franklin M, Cowen P J, Nutt D J
Reckitt and Colman Psychopharmacology Unit, School of Medical Sciences, Bristol, U.K.
Psychoneuroendocrinology. 1992 May-Jul;17(2-3):261-6. doi: 10.1016/0306-4530(92)90066-g.
To examine the role of alpha 2-adrenoceptors in the control of cortisol and ACTH, hormone responses to the selective alpha 2-antagonist idazoxan were studied in 12 normal volunteers. Plasma cortisol and ACTH were measured from 0930h-1230h on three occasions: before, on the 1st day, and on the 22nd day of an open treatment trial with idazoxan 40 mg administered three times per day. Compared with pretreatment cortisol levels, acute but not chronic idazoxan treatment attenuated the normal diurnal fall in plasma cortisol. Plasma ACTH concentrations were not altered by either dose of idazoxan. The attenuation of the diurnal fall in cortisol after acute idazoxan may be mediated through increased central availability of norepinephrine, and is similar to responses after high doses of the less selective alpha 2-antagonist yohimbine. Activity of central noradrenergic neurons appears to be reduced or normalized by chronic idazoxan, indicated by restoration of the normal diurnal fall in cortisol.
为研究α2-肾上腺素能受体在皮质醇和促肾上腺皮质激素（ACTH）调控中的作用，对12名正常志愿者进行了激素对选择性α2拮抗剂咪唑克生反应的研究。在一项开放治疗试验中，每日三次给予40mg咪唑克生，在三个时间点（治疗前、第1天和第22天）的0930h - 1230h测定血浆皮质醇和ACTH。与治疗前皮质醇水平相比，急性而非慢性咪唑克生治疗减弱了血浆皮质醇正常的昼夜下降。两种剂量的咪唑克生均未改变血浆ACTH浓度。急性给予咪唑克生后皮质醇昼夜下降的减弱可能是通过增加去甲肾上腺素的中枢可用性介导的，并且与高剂量的选择性较低的α2拮抗剂育亨宾后的反应相似。慢性给予咪唑克生后，中枢去甲肾上腺素能神经元的活性似乎降低或恢复正常，这表现为皮质醇正常昼夜下降的恢复。
