A. Schmid et al., FREE PLASMA-CATECHOLAMINES IN SPINAL-CORD INJURED PERSONS WITH DIFFERENT INJURY LEVELS AT REST AND DURING EXERCISE, Journal of the autonomic nervous system, 68(1-2), 1998, pp. 96-100
Spinal cord lesion leads to an interruption of pathways from brain to
the peripheral sympathetic nervous system, which results in pathologic
al changes in sympathetic innervation. Free epinephrine (E), norepinep
hrine (NE) and dopamine (DA) were measured in 30 tetraplegics (TETRA).
15 high-lesion paraplegics (T-1 and T-4, HPARA). 15 paraplegics with
injuries between T-5 and T-10 (MPARA), 15 low-lesion paraplegics (belo
w T-10, LPARA) and 16 non-handicapped control persons (C) at rest, at
60 and 100% of maximal oxygen consumption during graded wheelchair erg
ometry (WCE). The TETRA showed significant lower E and NE levels st re
st and only slight increases during physical exercise. The E and NE co
ncentrations of the paraplegics with a lesion below T-5 were significa
ntly higher than those of the high-lesion paraplegics. as well as thos
e of the control persons at every point in the study. All paraplegics
and the control persons showed, at submaximal and maximal exercise, a
significant increase in NE. Only a slight increase in E in HAPRA was s
hown. No differences were found at rest and during exercise in E and N
E levels in the MPARA and LPARA. No significant differences were found
in the dopamine concentration at rest or during exercise for any of t
he groups. In summary, different levels of lesion and the resulting in
terruption to sympathetic pathways in the spinal cord are decisive fac
tors in the degree of impairment of sympathetic innervation in SCI per
sons. Tetraplegics show less preganglionic resting activity because of
interruption of impulses from central centers and no considerable sti
mulation of the sympathetic nervous system during maximal exercise. In
dividuals with high paraplegia have a partial impairment of catecholam
ine release. especially of epinephrine. at rest and during exercise. P
araplegics with a lesion level below T-5 showed an augmented basal and
exercise-induced upper spinal thoracic sympathetic activity in compar
ison to control persons. (C) 1998 Elsevier Science B.V.