David Richard B, Menani José V, De Luca Laurival A
Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
Appetite. 2008 Jul;51(1):82-9. doi: 10.1016/j.appet.2007.12.003. Epub 2007 Dec 23.
The aim of this work was to test mineral preference in hydrated rats that received a pulse intracerebroventricular (icv(p)) injection of ANG II at a dipsogenic dose (50 ng). The icv(p) ANG II induced a four-fold higher ingestion of 0.15M NaHCO(3) than of other mineral solutions at palatable concentrations (0.15M NaCl, 0.05 mM CaCl(2) and 0.01 M KCl) in a five-bottle test with water available in a fifth bottle; water intake was not consistently high in this test. Contrary to what is predicted by the mineralocorticoid/angiotensin II synergy hypothesis, the 0.15M NaCl intake in the five-bottle test was not enhanced by icv(p) ANG II preceded by deoxycorticosterone (DOCA) treatment (2.5mg/day for 3 days); neither was the NaHCO(3) intake. This result contrasted with the vigorous ingestion of both isotonic sodium solutions, but mostly of NaCl, rather than of other fluids, by sodium-depleted (furosemide 10mg sc+24h removal ambient sodium) rats in a sodium appetite test. The results suggest that mineralocorticoid combined to icv(p) ANG II does not simulate the sodium preference shown during sodium appetite. The results also show that a dipsogenic dose of central ANG II induces a reliable ingestion of isotonic sodium bicarbonate in the rat.
本研究的目的是测试水合大鼠在接受致渴剂量（50 ng）的血管紧张素II脑室内脉冲注射（icv(p)）后的矿物质偏好。在五瓶测试中，第五瓶提供水，icv(p)血管紧张素II诱导的0.15M NaHCO₃摄入量比其他适口浓度（0.15M NaCl、0.05 mM CaCl₂和0.01M KCl）的矿物质溶液高四倍；在此测试中，水摄入量并不持续很高。与盐皮质激素/血管紧张素II协同假说所预测的相反，在五瓶测试中，icv(p)血管紧张素II在脱氧皮质酮（DOCA）治疗（2.5mg/天，共3天）之前，并未增加0.15M NaCl的摄入量；NaHCO₃摄入量也未增加。这一结果与钠缺乏（10mg速尿皮下注射+24小时去除环境钠）大鼠在钠食欲测试中大量摄入两种等渗钠溶液（但主要是NaCl，而非其他液体）形成对比。结果表明，盐皮质激素与icv(p)血管紧张素II联合使用并不能模拟钠食欲期间表现出的钠偏好。结果还表明，致渴剂量的中枢血管紧张素II能诱导大鼠可靠地摄入等渗碳酸氢钠。
