The investigation of possible roles of central 5-HT 7 receptors in antipyretic effect mechanism of paracetamol in LPS-induced hyperthermia model of mice

This study aimed to investigate the role of the 5-HT receptor in fever mechanisms and its possible effect on the antipyretic mechanism of paracetamol. The study consisted of eight experimental groups and one control group. Group I: healthy, II: LPS, III: LPS + PARA, IV: LPS + AGO, V: LPS + ANTA, VI: LPS + AGO + ANTA, VII: LPS + AGO + PARA, VIII: LPS + ANTA + PARA, and IX: LPS + AGO + ANTA + PARA. Rectal temperatures were measured with a rectal thermometer. At the end of the experiment, tissues were examined molecularly. Real-time PCR mRNA expression analyses were performed for the 5-HT7 receptor, IL-6, and TNF-α in hypothalamus tissue. The mean differences in rectal temperature increased in the LPS, LPS + ANTA, and LPS + AGO + ANTA groups when compared to the healthy group and decreased in the LPS + PARA, LPS + AGO, LPS + AGO + PARA, and LPS + AGO + ANTA + PARA groups when compared to the healthy group. The IL-6 and TNF-α mRNA expression increased in the LPS, LPS + ANTA, and LPS + AGO + ANTA groups when compared to the healthy group in the 2nd and 4th hours. The IL-6 and TNF-α expression decreased in the LPS + PARA, LPS + AGO, LPS + AGO + PARA, and LPS + AGO + ANTA + PARA groups when compared to the LPS group in the 2nd and 4th hours. The 5-HT receptor mRNA expression increased in the LPS group when compared to the healthy group in the 2nd hour. The 5-HT receptor mRNA expression decreased in the LPS + AGO and LPS + AGO + PARA groups when compared to the LPS group in the 2nd hour. The 5-HT receptor mRNA expression increased the in LPS + ANTA and LPS + ANTA + PARA groups when compared to the LPS group in the 2nd hour. The 5-HT receptor is a potential defense mechanism in stopping fever and the antipyretic property of paracetamol is not due to the 5-HT receptor.