Cardiovascular responses to vaginocervical stimulation in the spinal cord-transected rat

Abstract

The present study ascertained whether increases in heart rate (HR) and systolic blood pressure (SBP) produced by vaginocervical stimulation (VS; 500 g force) persist in the unanesthetized rat after chronic spinal cord transection at selected levels. Three groups were used: spinal cord transection at T7 ( n = 10) or L5 ( n = 10) or a sham-operated control group (Sh, n = 10). In the Sh group, VS increased significantly both HR, by 95 ± 14.3 beats/min (bpm) (22 ± 3.7% above baseline), and BP, by 37 ± 5.7 mmHg (37 ± 7.7% above baseline), confirming earlier findings. In the T7 group, VS significantly decreased HR by 107 ± 21.4 bpm (27 ± 4.1% below baseline) and increased BP by 41.3 ± 12.9 mmHg (32 ± 8.3% above baseline). In response to VS, HR increased in every rat in the Sh group and decreased in every rat in the T7 group. In the L5 group, VS failed to significantly affect HR or BP. In the present study, specific levels of spinal cord transection produced differential HR and BP responses to VS in the rat. A model is presented addressing the component responses of autonomic dysreflexia that can occur, contingent on the level of spinal cord injury, in women during parturition or sexual intercourse.