Roth J D, Rowland N E
Department of Psychology, University of Florida, Gainesville 32611-2250, USA.
Physiol Behav. 1998 Feb 15;63(4):729-32. doi: 10.1016/s0031-9384(97)00522-2.
Nitric oxide (NO) has been implicated centrally as an inhibitory neuromodulator, acting in short feedback loops. Neurons capable of NO synthesis have been localized in various thirst-related hypothalamic nuclei. Intracerebroventricular (icv) injection of L-arginine (L-arg), the precursor for NO, has previously been shown to attenuate both dehydration- and angiotensin II (Ang II)-induced drinking behavior. The present study further examines the effects of L-arg on drinking. We confirmed that icv administration of L-arg (50 microg) reduced water intakes induced by both 24 h water deprivation and icv Ang II (250 ng). We additionally showed that L-arg inhibited the water intake induced by peripheral injection of Ang II and the intake of 0.3 M NaCl following 24 h sodium depletion. We demonstrated the behavioral specificity of L-arg treatment by showing that it did not inhibit the intake of sucrose in food deprived rats and did not act as an unconditional stimulus for the formation of a conditioned taste aversion. These results lend further support to the idea that NO plays a role in modulating fluid balance and drinking behavior.
一氧化氮（NO）在中枢被认为是一种抑制性神经调节剂，通过短反馈回路发挥作用。能够合成NO的神经元已定位在与口渴相关的各种下丘脑核团中。此前已表明，脑室内（icv）注射L-精氨酸（L-arg），即NO的前体，可减弱脱水和血管紧张素II（Ang II）诱导的饮水行为。本研究进一步探讨L-arg对饮水的影响。我们证实，icv给予L-arg（50微克）可减少24小时禁水和icv注射Ang II（250纳克）所诱导的饮水量。我们还表明，L-arg可抑制外周注射Ang II所诱导的饮水以及24小时缺钠后0.3 M NaCl的摄入量。我们通过证明L-arg处理不抑制食物剥夺大鼠的蔗糖摄入量，且不作为形成条件性味觉厌恶的无条件刺激，展示了L-arg处理的行为特异性。这些结果进一步支持了NO在调节水平衡和饮水行为中起作用的观点。
