Effects of TRPV1 on LPS-induced fever and the content of Ca2+ and cAMP in hypothalamus in rats

• 1、China Medical University

Abstract：Aim To observe the effect of TRPV1 on the febrile response in fever ras, and further to investigate TRPV1 action in thermoregulation and the possible central mechanism. Methods Forty-eight rats were divided randomly into 4 groups: the control group (N), capsazepine group (CPZ), LPS-feverish group (L), the capsazepine+LPS-feverish group (CPZ+LPS). Changes in body temperature were continually observed; rats were put to death immediately at the peak of fever, [Ca2+]i was measured by the technique of Fura-2/AM calciumions fluorescence indicator; the content of cAMP in hypothalamus were measured by radioimmunoassay. Results (1) The sequence of the maximum change of temperature (ΔTmax) from high to low: group CPZ+LPS > group LPS > group CPZ> group N; ΔT (300~480 min) and TRI8 of group CPZ+LPS was significantly higher than group LPS (P <0.01); (2) At the peak of fever,[Ca2+]i of group CPZ+LPS was significantly lower than the other three (P <0.01);(3) But the content of cAMP in hypothalamus of group CPZ+LPS was the highest (P <0.01) . Conclusion It was possible that capsazepine changed intra-cellular [Ca2+]i by blocking TRPV1 channel in hypothalamus ,and then effected LPS-induced fever.

Keywords： lipopolysaccharide (LPS) fever transient receptor potential vanilloid 1 (TRPV1) Cyclic Adenosine monophosphate (cAMP) [Ca2+]i