Vagotomy modifies but does not eliminate the increase in body temperature following burn injury in rats.
BACKGROUND
Rats with burn injury to > or = 50% of the BSA demonstrate a significant increase in body temperature (T(B)) during light hours, and decrease of circadian variation in T(B). This study investigated the hypothesis that part or all of the signal for increased T(B) in rats with burn injury is transmitted to the central nervous system by way of afferent vagal fibers.


METHODS
Four groups of animals were studied: Burn-Sham Vagotomy; Control-Sham Vagotomy; Burn-Vagotomy and Control-Vagotomy. Anesthetized animals had bilateral subdiaphragmatic vagotomy (VagX) or sham VagX performed, and AM radio transmitters were implanted in the peritoneal cavity for the purpose of recording T(B) and activity index (AI). Following a one week recovery period, burn animals received scald burns equal to 50.3 +/- 2.5% BSA.


RESULTS
The main effect of VagX upon T(B) was a small but significant reduction in T(B) during dark hours. At least 87% of this decrease in post-burn T(B) was also present for the control vagotomy group. Vagotomy had no effect on the increase in T(B) for the burn groups during light hours. During dark hours, VagX significantly reduced T(B) in burns and controls, and burn injury significantly reduced activity.


CONCLUSIONS
One may speculate that afferent vagal signals are partially responsible for maintenance of T(B), with or without burn injury, and that the major signal for increase in T(B) for animals with burn injury is not a neural one via afferent vagal pathways.
Caldwell
F T
FT
University of Arkansas, Department of Surgery, Little Rock 72205, USA. wallacebonnyb@exchange.uams.edu
Graves
D B
DB
Wallace
B H
BH
D000344:Afferent Pathways / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001830:Body Surface Area; D001831:Body Temperature / Q000502:physiology*; D002056:Burns / Q000503:physiopathology*; D002490:Central Nervous System / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D004195:Disease Models, Animal; D005334:Fever / Q000503:physiopathology*; D008297:Male; D009043:Motor Activity / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*