Hong Y G, Yashpal K, Henry J L
Department of Physiology, McGill University, Montreal, Que., Canada.
Brain Res. 1989 Oct 9;499(1):169-73. doi: 10.1016/0006-8993(89)91148-7.
Experiments were done to determine the influence of spinal glycinergic mechanisms in regulating sympathetic output to the heart and vessels in the anaesthetized male Sprague-Dawley rat. Intrathecal administration of 65 (n = 6) and 130 (n = 8) nmol of strychnine, but not of a lower dose (32.5 nmol, n = 8), to the second thoracic segment increased heart rate within one minute (P less than 0.01). Similar administration of artificial cerebrospinal fluid (n = 16) had no effect. The increase in heart rate in response to strychnine peaked at 5-7 min (+35.1 +/- 5.8 bpm with 130 nmol), and slowly returned toward baseline values over the next 25 min. Arterial pressure was unaffected by this treatment. These effects were not mimicked by administration of strychnine (n = 6) at the third lumbar spinal level or by intravenous infusion of strychnine (n = 4) and were abolished by systemic injection of hexamethonium (n = 6). The results suggest that there is a tonic glycine-mediated inhibition of sympathetic output at the spinal level.
开展实验以确定脊髓甘氨酸能机制在调节麻醉的雄性Sprague-Dawley大鼠心脏和血管交感输出中的作用。向第二胸段鞘内注射65（n = 6）和130（n = 8）nmol的士的宁，但较低剂量（32.5 nmol，n = 8）则无此作用，注射后1分钟内心率增加（P < 0.01）。注射人工脑脊液（n = 16）则无类似作用。对士的宁反应的心率增加在5 - 7分钟时达到峰值（130 nmol时为+35.1 ± 5.8次/分钟），并在接下来的25分钟内缓慢恢复至基线值。此处理对动脉血压无影响。在第三腰段脊髓水平注射士的宁（n = 6）或静脉输注士的宁（n = 4）均未模拟出这些效应，且全身注射六甲铵（n = 6）可消除这些效应。结果表明，在脊髓水平存在由甘氨酸介导的对交感输出的紧张性抑制。
