[21] In animal studies, BNP infusion modified ANS activity by reinforcing reflex bradycardia. [8] Moreover, BNP infusion at doses in the physiologic range resulted in a reduction in cardiac sympathetic activity in both healthy subjects and patients with heart failure. [9] Whether this inhibitory effect is due to a direct action of the natriuretic peptide, or whether it is indirectly related to a reduction in cardiac filling pressures, remains to be determined. This evidence concerns the gene NPPB and heart failure.