Ryan K L, Frei M R, Jauchem J R
Department of Biology, Trinity University, San Antonio, Texas 78212, USA.
Shock. 1997 Jan;7(1):70-6. doi: 10.1097/00024382-199701000-00010.
Sustained exposure to radiofrequency radiation of millimeter wave (MMW) length produces hyperthermia and subsequent circulatory failure. This study sought to determine whether this phenomenon is altered by chronic pretreatment with the nitric oxide (NO) synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Rats drank either 1) water, 2) water + L-NAME, or 3) water + L-NAME + L-arginine (at 20 and 50 times the dose of L-NAME) for 14 days. Ketamine-anesthetized rats were exposed to MMW until mean arterial blood pressure (MAP) fell to 75 mmHg, at which point MMW exposure was discontinued. MAP initially increased during exposure in all groups; the pressor response in L-NAME-treated rats was greater than that in water-drinking rats. Subsequently, MAP fell in all groups. The MMW exposure time required to reach MAP = 75 mmHg was significantly reduced in L-NAME-treated rats, although survival times (post-MMW) of L-NAME-treated and control rats were not statistically different. Coadministration of L-arginine abolished the enhanced pressor response produced by L-NAME, but did not completely reverse the shortened MMW exposure time in L-NAME-treated rats. Thus, chronic NO synthesis inhibition with L-NAME reduces the ability of rats to withstand 35 GHz microwave heating, suggesting that NO does not mediate the hypotension produced by this form of hyperthermia.
持续暴露于毫米波（MMW）长度的射频辐射会导致体温过高及随后的循环衰竭。本研究旨在确定这种现象是否会因用一氧化氮（NO）合成抑制剂Nω-硝基-L-精氨酸甲酯（L-NAME）进行慢性预处理而改变。大鼠连续14天饮用以下三种溶液之一：1）水；2）水+L-NAME；3）水+L-NAME+L-精氨酸（剂量为L-NAME的20倍和50倍）。用氯胺酮麻醉的大鼠暴露于毫米波，直至平均动脉血压（MAP）降至75 mmHg，此时停止毫米波暴露。在暴露期间，所有组的MAP最初均升高；L-NAME处理组大鼠的升压反应大于饮水组大鼠。随后，所有组的MAP均下降。在L-NAME处理的大鼠中，达到MAP = 75 mmHg所需的毫米波暴露时间显著缩短，尽管L-NAME处理组和对照组大鼠的存活时间（毫米波暴露后）无统计学差异。同时给予L-精氨酸消除了L-NAME产生的增强升压反应，但并未完全逆转L-NAME处理大鼠缩短的毫米波暴露时间。因此，用L-NAME进行慢性NO合成抑制会降低大鼠耐受35 GHz微波加热的能力，这表明NO并不介导这种形式的体温过高所产生的低血压。
