Ganesan R, Sumners C
Department of Physiology, University of Florida, College of Medicine, Gainesville 32610.
Brain Res. 1989 Oct 9;499(1):121-30. doi: 10.1016/0006-8993(89)91141-4.
The effect of a short-term, acute treatment with a glucocorticoid, dexamethasone sodium phosphate, on the drinking induced by angiotensin II (AII) was investigated in a series of experiments. Initial studies indicated that a single injection of dexamethasone (700-750 micrograms/kg, i.p.) reduced food intake, body weight and water intake for up to 48 h, but had little effect on blood pressure when it was measured 6 h subsequent to the injection. The drinking elicited by peripherally administered AII (200 micrograms/kg, s.c.) was enhanced if the glucocorticoid (700 micrograms/kg, i.p.) was given 3 h or 6 h prior to the dipsogen. There was no effect of pretreatment with the steroid if the drinking test was delayed by 24 h. The subsequent experiment showed that the glucocorticoid effect on AII-stimulated drinking was dose dependent (100 micrograms-1600 micrograms/kg). The drinking stimulated by intracerebroventricular (i.c.v.) AII (2.5 ng) was enhanced in terms of volume and total duration by prior treatment with dexamethasone, but i.c.v. carbachol (200 ng)-induced drinking remained unaffected. The final study showed that binding of AII to its receptors in five different areas of the rat brain was not affected by prior treatment with dexamethasone.
在一系列实验中，研究了短期急性给予糖皮质激素地塞米松磷酸钠对血管紧张素II（AII）诱导饮水的影响。初步研究表明，单次注射地塞米松（700 - 750微克/千克，腹腔注射）可使食物摄入量、体重和水摄入量在长达48小时内减少，但在注射后6小时测量血压时，对血压影响不大。如果在给予致渴剂前3小时或6小时给予糖皮质激素（700微克/千克，腹腔注射），则外周给予AII（200微克/千克，皮下注射）引起的饮水会增加。如果饮水试验延迟24小时，类固醇预处理则没有效果。随后的实验表明，糖皮质激素对AII刺激饮水的作用是剂量依赖性的（100微克 - 1600微克/千克）。预先用地塞米松治疗可使脑室内（i.c.v.）给予AII（2.5纳克）刺激的饮水在量和总持续时间上增加，但i.c.v.给予卡巴胆碱（200纳克）诱导的饮水不受影响。最终研究表明，预先用地塞米松治疗不会影响AII与大鼠脑五个不同区域受体的结合。
