Does postsynaptic α1-adrenergic receptor supersensitivity contribute to autonomic dysreflexia?

被引:29
作者
Landrum, LM [1 ]
Thompson, GM [1 ]
Blair, RW [1 ]
机构
[1] Univ Oklahoma, Hlth Sci Ctr, Dept Physiol, Oklahoma City, OK 73190 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 1998年 / 274卷 / 04期
关键词
hypertension; spinal cord injury; phenylephrine;
D O I
10.1152/ajpheart.1998.274.4.H1090
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Quadriplegics often experience periods of severe hypertension known as autonomic dysreflexia. Clinically these events have been well documented, but the mechanisms for mediating autonomic dysreflexia remain unclear. We used a chronic rat mo del to investigate the potential development of supersensitivity at postsynaptic alpha(1)-adrenergic receptors as a contributing factor to the exaggerated sympathetic response characteristic of autonomic dysreflexia. Adult male Wistar and Sprague-Dawley rats were anesthetized and given spinal transection at T-5 After 30 days, rats were reanesthetized and arterial and venous catheters implanted. Twenty-four hours later, colorectal distension (CRD) was used to evoke autonomic dysreflexia in conscious, spinalized rats. To gauge changes in alpha(1)-receptor sensitivity, we assessed mean arterial pressure (MAP) in response to intravenous phenylephrine (PE) infusions. No consistent differences were observed between intact and spinalized rats. Therefore, supersensitivity of alpha(1)-receptors cannot completely account for the hypertensive bouts associated with autonomic dysreflexia. Ln addition, while attempting to develop an appropriate model for autonomic dysreflexia, we discovered that spinalized Wistar rats exhibited MAP responses characteristic of autonomic dysreflexia, whereas lesioned Sprague-Dawley rats did not, when subjected to CRD. Thus Wistar rats provide a better animal model for autonomic dysreflexia.
引用
收藏
页码:H1090 / H1098
页数:9
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