In this study, the levels of Ang II and superoxide anions in the PVN were increased in CHF rats, IMD in the PVN decreased superoxide anions level and attenuated Ang II-induced CSAR response and superoxide anions increase in the PVN in CHF rats, which indicate that the inhibitory effect of IMD on CSAR is partially through inhibiting Ang II-induced superoxide anions. This evidence concerns the gene AGT and congestive heart failure.