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Discordant Vasomotor and Sudomotor Activity During Heat Stress in Persons with Spinal Cord Injury
Author(s) -
Trbovich Michelle,
Wu Yubo,
Kellogg Dean
Publication year - 2018
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.2018.32.1_supplement.722.6
Subject(s) - sudomotor , vasomotor , medicine , tetraplegia , spinal cord injury , cholinergic , sympathetic nervous system , autonomic nervous system , paraplegia , microneurography , endocrinology , baroreflex , spinal cord , anesthesia , blood pressure , heart rate , psychiatry
Objective Persons with spinal cord injury (SCI) have compromised thermoregulatory vasomotor and sudomotor activity. During heat stress, impaired cutaneous vasodilation obviates skin blood flow (SkBF) increases and sweating responses (SR) are also impaired. Thus SCI persons have difficulty maintaining thermal homeostasis in heat stress. Our understanding of changes in the peripheral autonomic nervous system post SCI is incomplete. In non‐SCI persons, sympathetic cholinergic mechanisms effect increases in both SkBF and SR presumably through one set of nerves; however, definitive proof is lacking. Indeed, cholinergic vasodilator nerves and cholinergic sudomotor nerves could actually be anatomically separate. Interestingly, in the 1970s, it was reported that during heat stress, persons with complete SCI have skin regions where SkBF increases without concomitant SR increases and other regions where SR increases without concomitant SkBF increases. These results suggest that efferent cholinergic sympathetic vasomotor nerves and efferent cholinergic sympathetic sudomotor nerves are separate. Methods Three persons (C4 AIS B/tetraplegia, T8 AIS A/paraplegia and able‐bodied) underwent indirect heat stress until core temperature (Tcore) rose 0.8°C. Areas 10 cm above and 20 cm below neurological level of injury (NLOI) of SCI persons were left uncovered so as to avoid local heating effects. After Tcore elevation, SkBF responses were measured by laser Doppler imaging (LDI) while SR were assessed via the starch iodine test. Results The person with tetraplegia showed increases in SkBF as indexed by LDI both above and below the NLOI down to T2 dermatomal level but demonstrated no intact SR areas. The person with paraplegia demonstrated increased SR down to T9 and increases in SkBF down to T12 dermatomal levels. Finally, the able‐bodied (AB) person LDI scan from the T6 to T12 dermatomal levels demonstrated intact SkBF and intact SR throughout the entire area. In both SCI persons, the skin areas of preserved SkBF responses were discordant with those of SR during heat stress. The AB person demonstrated no discordant responses as SkBF and SR. Conclusion This pilot data confirms discordant SkBF and SR responses in persons with tetraplegia and paraplegia and demonstrates that SCI persons can serve as a model to further investigate the neurological reflex controls of SkBF and SR during heat stress. Furthermore, these data suggests that cholinergic sympathetic vasomotor nerves and efferent cholinergic sympathetic sudomotor nerves may be separate. Support or Funding Information Veteran's Affairs Rehabilitation Research and Development, Career Development Award This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .