Osborn J W, Taylor R F, Schramm L P
Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
Am J Physiol. 1990 Jan;258(1 Pt 2):R169-74. doi: 10.1152/ajpregu.1990.258.1.R169.
Although it is well established that patients with cervical spinal cord injury are prone to acute, marked, hypertensive episodes, i.e., autonomic hyperreflexia, the specific mechanisms mediating this sometimes-fatal phenomenon are not completely understood. In this report, we describe the preparation and characterization of a rat model of chronic cervical spinal cord injury and autonomic hyperreflexia. Adult male Sprague-Dawley rats were chronically instrumented with arterial, venous, and gastric catheters. Beginning the first day after a complete cervical spinal transection (CST) and continuing for 1 wk, acute hypertensive responses to a modest increase of urinary bladder pressure (0-20 mmHg) were studied. Mean arterial pressure increased 25.9 +/- 4.8 mmHg during bladder distension the first day after CST. This response was not significantly different 3, 5, and 7 days after CST (overall average = 18.0 +/- 2.3 mmHg). The pressor response to bladder distension was completely abolished by intravesical lidocaine and autonomic ganglionic blockade (atropine + hexamethonium). Responses to bladder distension were not observed after the administration of chloralose anesthesia. We conclude that after cervical spinal transection the rat exhibits autonomic hyperreflexia similar to that seen in humans with spinal injury. Furthermore, autonomic hyperreflexia is completely established within 24 h after CST in the rat. Finally, some spinal autonomic reflexes are suppressed by chloralose anesthesia in the rat.
虽然颈脊髓损伤患者易发生急性、显著的高血压发作，即自主神经反射亢进，这一点已得到充分证实，但介导这种有时会致命现象的具体机制尚未完全明确。在本报告中，我们描述了慢性颈脊髓损伤和自主神经反射亢进大鼠模型的制备及特性。成年雄性Sprague-Dawley大鼠长期植入动脉、静脉和胃导管。从完全性颈脊髓横断（CST）后的第一天开始，持续1周，研究膀胱压力适度升高（0 - 20 mmHg）时的急性高血压反应。CST后第一天膀胱扩张期间平均动脉压升高25.9±4.8 mmHg。CST后3天、5天和7天该反应无显著差异（总体平均值 = 18.0±2.3 mmHg）。膀胱扩张引起的升压反应可被膀胱内利多卡因和自主神经节阻滞（阿托品 + 六甲铵）完全消除。给予水合氯醛麻醉后未观察到对膀胱扩张的反应。我们得出结论，颈脊髓横断后大鼠表现出与脊髓损伤患者相似的自主神经反射亢进。此外，大鼠在CST后24小时内自主神经反射亢进完全形成。最后，大鼠中的一些脊髓自主神经反射可被水合氯醛麻醉抑制。
