Thermal conditions influence changes in body temperature induced by intragastric administration of capsaicin in mice

Abstract

Capsaicin has been reported to have unique thermoregulatory actions. However, changes in core temperature after the administration of capsaicin are a controversial point. Therefore, we investigated the effects of environmental thermal conditions on changes in body temperature caused by capsaicin in mice. We showed that intragastric administration of 10 and 15 mg/kg capsaicin increased tail temperature and decreased colonic temperatures in the core temperature (CT)-constant and CT-decreasing conditions. In the CT-increasing condition, 15 mg/kg capsaicin increased tail temperature and decreased colonic temperature. However, 10 mg/kg capsaicin increased colonic temperature. Furthermore, the amount of increase in tail temperature was greater in the CT-decreasing condition and lower in the CT-increasing condition, compared with that of the CT-constant condition. These findings suggest that the changes in core temperature were affected by the environmental thermal conditions and that preliminary thermoregulation state might be more important than the constancy of temperature to evaluate the effects of heat diffusion and thermogensis.

Changes in TRPV1-Mediated Physiological Function in Rats Systemically Treated With Capsaicin on the Neonate

“…The difference between TRPV1 antagonist and neonatal capsaicin treatment is that the hyperthermic effect of capsaicin treatment in neonates is long-lasting [10]. Previous studies on body temperature changes following topical or neonatal capsaicin treatment are listed in Table 3 [13,[38][39][40][41]. Numerous studies have been carried out on the analysis of the effect of hyperthermia on immune cell subsets targeting the tumor, and upregulation of interleukin induced T lymphocyte proliferation by TRPV-1 activation was found to be increased by hyperthermia [42].…”

Vagus nerve is involved in the changes in body temperature induced by intragastric administration of 1,8-cineole via TRPM8 in mice

“…Intrascapular brown adipose tissue (IBAT) temperature, an index of local non-shivering thermogenesis, was measured with the same thermistor placed around the IBAT. The indices were the same as those described in previous reports [13,15]. Thermistors were connected to a temperature recorder (NR-1000, Keyence, Osaka, Japan).…”

“…Body temperatures were measured as described previously with a slight modification [15]. Briefly, the mice were fasted for approximately 2 h (0900-1100 h), but had free access to water.…”