Catecholamine assays in a rat model for autonomic dysreflexia.

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.