Northpoint Surgery and Laser Center, West Palm Beach, FL, USA.
Neurol Sci. 2012 Feb;33(1):69-78. doi: 10.1007/s10072-011-0661-x. Epub 2011 Jun 28.
We have examined the role of inducible nitric oxide synthase (iNOS) within the dorsolateral periaqueductal gray mater (dlPAG) on cardiovascular responses during mechanical, thermal, and cold nociception in anesthetized rats. Mechanical stimulus was applied by a unilateral hindpaw pinch for 10 s that increased mean arterial pressure (MAP) and heart rate (HR). Bilateral microdialysis of a selective iNOS inhibitor, aminoguanidine (AGN; 10 μM), into the dlPAG for 30 min augmented MAP and HR responses during a mechanical stimulation. The cardiovascular responses recovered following discontinuation of the drug. Heat stimulus was generated by immersing one hindpaw metatarsus in a water bath at 52°C for 10 s, and this increased MAP and HR. Administration of AGN into the PAG potentiated these cardiovascular responses. Cardiovascular responses recovered following discontinuation of the drug. In contrast, application of a cold stimulus by immersing one hindpaw at 10°C for 10 s resulted in depressor and bradycardic responses. A second cold stimulus resulted in a response that was not significantly different from that prior to or after recovery from the AGN infusion. These results demonstrate that iNOS within the dlPAG plays a differential role in modulating cardiovascular responses during mechanical-, heat-, and cold-mediated nociception.
我们研究了诱导型一氧化氮合酶（iNOS）在麻醉大鼠机械、热和冷伤害感受期间背外侧导水管周围灰质（dlPAG）中的作用。机械刺激通过单侧后爪捏 10 秒施加，增加平均动脉压（MAP）和心率（HR）。双侧微透析选择性 iNOS 抑制剂氨基胍（AGN；10 μM）30 分钟，增加机械刺激期间的 MAP 和 HR 反应。药物停止后，心血管反应恢复。热刺激通过将一只后爪跖骨浸入 52°C 的水浴中 10 秒产生，这增加了 MAP 和 HR。AGN 给药增强了这些心血管反应。药物停止后，心血管反应恢复。相比之下，将一只后爪浸入 10°C 的冷刺激 10 秒导致降压和心动过缓反应。第二次冷刺激的反应与 AGN 输注前后恢复后的反应没有显著差异。这些结果表明，dlPAG 中的 iNOS 在调节机械、热和冷介导的伤害感受期间的心血管反应中发挥了不同的作用。
