F Y Chiou-Tan1, C S Robertson, G C Chiou. 1. Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, USA.
Abstract
OBJECTIVE: To determine if norepinephrine (NE) levels increased during autonomic dysreflexia (AD) hypertension in spinal cord injured rats. DESIGN: Prospective, randomized study of three groups of eight rats that underwent C8 spinal cord transection. Two days postoperatively, catecholamine samples were collected from the animals as follows: group 1 without preoperative chemical sympathectomy using 6-hydroxydopamine (6-OH DA) or induced AD; group 2 with induced AD; and group 3, preoperative chemical sympathectomy with 6-OH DA and induced AD. SETTING: Basic science research laboratory in an academic institution. PARTICIPANTS: Sprague-Dawley male rats weighing 300g. INTERVENTION: Three episodes of induced AD hypertension with bowel distension for 1 minute. RESULTS: Results showed a significant difference between groups 1 and 2, 2 and 3, and 1 and 3 (p=.0002, ANOVA, Y1/2, post hoc Tukey). The mean NE levels in groups 1, 2, and 3 were 465+/-400 ng/mL, 1,328+/-1,116 ng/mL, and 31+/-61 ng/mL, respectively. CONCLUSION: NE increased during AD in the spinal cord injured rat. NE levels were effectively blocked by 6-OH DA when AD was induced. Knowledge of catecholamine levels in this process may assist in determining both pathophysiology and potential pharmacologic treatment options in future human studies.
OBJECTIVE: To determine if norepinephrine (NE) levels increased during autonomic dysreflexia (AD) hypertension in spinal cord injured rats. DESIGN: Prospective, randomized study of three groups of eight rats that underwent C8 spinal cord transection. Two days postoperatively, catecholamine samples were collected from the animals as follows: group 1 without preoperative chemical sympathectomy using 6-hydroxydopamine (6-OH DA) or induced AD; group 2 with induced AD; and group 3, preoperative chemical sympathectomy with 6-OH DA and induced AD. SETTING: Basic science research laboratory in an academic institution. PARTICIPANTS: Sprague-Dawley male rats weighing 300g. INTERVENTION: Three episodes of induced ADhypertension with bowel distension for 1 minute. RESULTS: Results showed a significant difference between groups 1 and 2, 2 and 3, and 1 and 3 (p=.0002, ANOVA, Y1/2, post hoc Tukey). The mean NE levels in groups 1, 2, and 3 were 465+/-400 ng/mL, 1,328+/-1,116 ng/mL, and 31+/-61 ng/mL, respectively. CONCLUSION: NE increased during AD in the spinal cord injured rat. NE levels were effectively blocked by 6-OH DA when AD was induced. Knowledge of catecholamine levels in this process may assist in determining both pathophysiology and potential pharmacologic treatment options in future human studies.