Expression of material mRNA in the hypothalamus and frontal cortex in a rat model of fatal hypothermia.

Diagnosis of fatal hypothermia is considered to be difficult in forensic practice because of the lack of any specific pathological findings. The mechanism that induces abnormal behavior such as undressing or hiding during the state of hypothermia has not been clarified. In order to solve these problems, we made a rat model of fatal hypothermia and investigated the expression of some mRNA within the hypothalamus and the frontal cortex. The expression of aldehyde dehydrogenase 6 family, member A1 (ALDH6A1), cocaine- and amphetamine-regulated transcript peptide (CARTPT), desmin (DES), heat shock 70kDa protein 4 (HSPA4), serotonin receptor 2A (HTR2A), opioid receptor, delta 1 (OPRD1) and transthyretin (TTR) supposedly related to fatal hypothermia was determined using quantitative real-time PCR. The expression of OPRD1 in the hypothalamus of fatal hypothermia was significantly increased, while the expression of TTR within the frontal cortex was significantly decreased compared to that in the control. These findings suggest that OPRD1 and TTR may be involved in thermoregulation at a low ambient temperature.