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Autonomic Responses to Psychological and Physiological Stressors in Spinal Cord Injury
Author(s) -
Bartels Matthew N.,
George Barbara J.,
Gates Gregory J.,
McKinley Paula S.,
De Meersman Ronald E.,
Sloan Richard P.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1428
Since complete spinal cord injury (SCI) leads to loss of central innervation of peripheral vasculature similar to accelerated aging, we compared autonomic reactivity (AR) between 7 complete T‐10 paraplegics (PARA) and 8 matched sedentary controls (CON) above and below the level of lesion during mental arithmetic (MA) and 30% oxygen challenge (O 2 ) by recording ECG and simultaneous arterial tonometry in the radial and dorsalis pedis arteries. In PARA, MA caused increased blood pressure (BP) with no AR change in either upper and lower compartments. Comparing PARA to CON, Vagal modulation (VM) was lower during MA [PARA 33 (19.6) versus CON 48 (18.1) msec 2 nu, (P <0.05)]. Baroreflex sensitivity (BRS) was lower for the PARA during the MA when compared to the CON [PARA 8.9 (4.9) msec/mmHg versus CON 18.4 (8.6) msec/mmHg ( P < 0.05)]. BRS decreased in PARA during MA [15.9 (14.4) versus 8.9 (4.9) msec/mmHg ( P < 0.05)] while CON showed no change to MA [baseline 20.3 (7.7) versus MA18.4 (8.6) msec/mmHg]. BP decreased following O 2 in both groups [PARA 134 (23.8) to 128 (24.3) mmHg]; CON [112 (19.5]) to 102 (15.5) ( P < 0.05)], while VM increased in CON compared to PARA [CON 17.3 versus PARA 2.3 msec 2 (nu), P < 0.01]. With O 2 , BRS was unchanged in both compartments for both groups. In conclusion, PARA experience a more unfavorable shift in AR during MA consistent with accelerated aging. However, with O 2 , a degree of AR is preserved below the level of the spinal injury, indicating that peripheral factors also contribute to maintaining vascular tone. Supported by the VIDDA foundation