BDNF and congestive heart failure: In addition, the number of BDNF-positive neurons in small-sized DRG subpopulations (mainly metabolically-sensitive IB4-positive neurons) was also moderately increased in L4-L6 DRGs of CHF rats compared to sham rats (26.8 ± 2.4% vs. 46.4 ± 8.3%, n = 5/each, p < 0.05).