NPPB and congestive heart failure: As shown in Fig. 2, following short-term VNS, serum levels of BNP decreased significantly in the rats of the CHF-VNS group (10.07±2.63, vs. 23.80±5.82 ng/ml, respectively; P=0.001), while the level of BNP did not alter significantly in the CHF-SS rats (19.95±5.22, vs. 23.56± 5.71 ng/ml, respectively; P>0.05).