Abstract
Background：The purpose of this study was to clarify the extent of the involvement of sympathetic
nerves and heat—induced vasodilation in renal microcirculatory changes during whole—body passive
heating.
Methods：Renal cortical blood flow, heart rate, systolic blood pressure, and NOS3mRNA, etc. were
measured and compared when TRPV4 was inhibited or beta receptors were blocked and rectal temperature
was maintained at 37℃ or 40℃ in mice.
Results：Passive thermothermia under TRPV4 inhibition significantly decreased renal cortical blood
flow by approximately 18.5％（p＜0.05）, accompanied by a decrease in NOS3mRNA expression. However,
there was no change in cardiac workload；passive hyperthermia under β—receptor blockade significantly
decreased cardiac workload and significantly decreased renal cortical blood flow by approximately
14.4％（p＜0.05）.
Conclusion：Our results suggest that sympathetic and thermotropic vasodilation are equally involved
in the regulation of renal microcirculation.
