Center of Excellence, James J. Peters Veterans Affairs Medical Center, Bronx, NY 10468, USA.
Arch Phys Med Rehabil. 2011 Nov;92(11):1789-95. doi: 10.1016/j.apmr.2011.03.022. Epub 2011 Jul 16.
To compare responses to head-up tilt (HUT) in individuals with chronic tetraplegia after midodrine hydrochloride (10 mg) versus nitro-L-arginine methyl ester (L-NAME, 1 mg/kg) administration.
Prospective comparative drug trial.
Veterans Affairs medical center.
Participants (N=7) were studied during 3 laboratory visits: no drug, midodrine (administered orally 30 min before HUT), and L-NAME (infused over a 60-min period).
Anti-hypotensive agents, midodrine, and L-NAME.
Mean arterial pressure (MAP), cerebral blood flow (CBF), and markers of the renin-angiotensin-aldosterone system (RAAS, plasma renin and serum aldosterone) were measured in the supine position at baseline (BL) and during a 45° HUT maneuver. Data were compared between BL and the average of 3 assessments collected during HUT.
Orthostatic MAP and CBF were increased with the midodrine and L-NAME groups compared with the no drug trial and the relationship between the change in MAP and CBF was significant (r=0.770; P<0.001). Both L-NAME and midodrine appeared to suppress the post-HUT RAAS response compared with no drug.
Increasing orthostatic blood pressure with L-NAME or midodrine appears to increase CBF and suppress the RAAS during HUT in persons with tetraplegia, although more data are needed to confirm these preliminary findings.
比较米多君（10mg）和硝基-L-精氨酸甲酯（L-NAME，1mg/kg）给药后慢性四肢瘫痪患者对直立倾斜（HUT）的反应。
前瞻性比较药物试验。
退伍军人事务医疗中心。
在 3 次实验室就诊期间研究了参与者（N=7）：无药物、米多君（在 HUT 前 30 分钟口服给予）和 L-NAME（在 60 分钟期间输注）。
抗低血压药物、米多君和 L-NAME。
仰卧位时的平均动脉压（MAP）、脑血流（CBF）和肾素-血管紧张素-醛固酮系统（RAAS，血浆肾素和血清醛固酮）标志物在基线（BL）和 45°HUT 操作期间进行测量。将 BL 与 HUT 期间收集的 3 次评估的平均值进行比较。
与无药物试验相比，米多君和 L-NAME 组的直立 MAP 和 CBF 增加，MAP 和 CBF 的变化之间存在显著关系（r=0.770；P<0.001）。与无药物相比，L-NAME 和米多君似乎都抑制了 HUT 后的 RAAS 反应。
在四肢瘫痪患者中，用 L-NAME 或米多君增加直立血压似乎会增加 CBF 并抑制 HUT 期间的 RAAS，尽管需要更多的数据来证实这些初步发现。
