AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 2 299-R302, Copyright © 1983 by American Physiological Society
Effect of p-chlorophenylalanine on thermoregulation in unrestrained rats
J. L. Giacchino, E. R. Schertel, J. M. Horowitz and B. A. Horwitz
p-Chlorophenylalanine (PCPA), a serotonin depletor, was used to investigate
thermoregulation of unrestrained unanesthetized rats exposed to warm
(approximately 32 degrees C) and cold (approximately 3 degrees C)
environments. PCPA (300 mg/kg, ip) was administered approximately 48-96 h
prior to the experimental trials. After 60 min of warm exposure,
PCPA-treated rats had a significantly smaller increase in mean tail
temperature (3.05 degrees C) and a greater increase in mean core
temperature (1.47 degrees C) than did the control rats (6.13 and 1.20
degrees C, respectively) as measured via chronically implanted thermistors.
A noninvasive method, infrared photography, was also used to monitor skin
temperatures following heat exposure. Changes were qualitatively similar to
those seen with thermistors, although differences between control and
PCPA-treated groups were not statistically significant. During cold
exposure, thermistor measurements indicated that the decrease in mean core
temperature of the PCPA-treated rats (0.62 degrees C) did significantly
differ from that of the controls (1.11 degrees C), whereas tail
temperatures did not. These data confirm other studies implicating
serotonin in the thermoregulation of rats. In particular, these results
show that in a warm environment, PCPA may alter, albeit subtly, peripheral
vasodilation in unrestrained rats.
