Cinnamaldehyde application decreases tail temperature in ovariectomized rats with and without estradiol administration

摘要

The aim of this study was to examine the effect of estradiol (E-2) on the thermoregulatory responses induced by cinnamaldehyde, a component extracted from cinnamon at 16 degrees C or 27 degrees C. The thermoneutral and subneutral experiments were performed to evaluate the augmented effect of cinnamaldehyde by cold exposure and the effect of cinnamaldehyde itself. Ovariectomized rats were implanted with a silastic tube with or without E-2 (E-2(+) and E-2(-) groups), and data loggers into the peritoneal cavity. After the application of 30% cinnamaldehyde or vehicle into the skin of the whole trunk of rats, the rats were exposed to 16 degrees C or 27 degrees C for 2 h. Body temperature (T-b) and tail temperature (T-tail) were measured using a data logger and thermography. After exposure, blood samples were obtained, and plasma catecholamine concentration were measured by high-performance liquid chromatography. In the E-2(-) group exposed to 27 degrees C, the change in T-b in rats applied cinnamaldehyde was significantly lower than that of rats applied vehicle. The change in T-tail in rats applied cinnamaldehyde was significantly lower than that of rats applied vehicle in both E-2(-) and E-2(+) groups at 27 degrees C and 16 degrees C. Plasma catecholamine concentration at 27 degrees C was not different among the groups. E-2 might not affect thermoregulatory responses induced by cinnamaldehyde application; however, it decreased T-tail in female rats.