Thermoregulatory Effects of Atropine in the Cold Using a Hypotrichotic Rat Model
Abstract
The objectives of this research were to determine the effects of atropine on thermoregulation and peripheral vasodilation in the cold. A conscious, confined but unrestrained, hypotrichotic (Wistar-Furth, fuzzy) rat model was used. Electromyography (EMG) was utilized to assess the shivering response of the trapezius muscle. An EMG frequency band between 3 Hz and 1 kHz was rectified, then integrated for determination of a shivering index. Infrared thermography was used to monitor dorsal body skin temperature as an indirect assessment of cutaneous blood flow. Rats were injected in the lumbar musculature with either 1 mg/kg atropine (A) or an equivalent volume (0.15 ml) of saline (S) 30 minutes after exposure to either 25 deg C, 18 deg C or 12 deg C. Data were then collected for an additional 90 minutes. There were no significant between group (A vs. S, p<0.05) differences in shivering, rectal temperature (T sub re), skin temperature or tail temperature at 25 deg C (n=6/group), 18 deg C (n=7/ group), or 12 deg C (n=12/group) . Modest within group decrements in T sub re, occurred between 10 and 90 min following A injection at 18 deg C and 12 deg C. A transient decline in shivering occurred following atropine administration at 12 deg C, but baseline levels were reached by 20 min post-injection. We concluded that intramuscular injection of A caused a small decrease in T sub re in a cold- stressed hypotrichotic rat model. However, this decrease could not be entirely explained by shivering inhibition nor by cutaneous vasodilation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1993
- Accession Number
- ADA273291
Entities
People
- Brianj. Gentile
- Criag R. Johnson
- Ralph P. Francesconi
- Roger W. Hubbard
Organizations
- United States Army Research Institute of Environmental Medicine