The number of nNOS-IR nerve cell bodies in the myenteric ganglia of 20-week HF diet mice increased, while the density index of nNOS-IR nerve cell bodies plus varicosities was reduced. LMMP preparations from 20-week SC (a) and HF (b) diet mice were stained with an antibody for nNOS to assess the packing density of nNOS IR nerve cell bodies and the density index of nNOS-IR cell bodies plus IR varicosities in the ganglia. Neuronal NOS-IR cell body packing density was increased in HF diet mice compared to SC diet mice (c; P = 0.042, n = 8, unpaired t-test). In contrast, the density index of nNOS-IR cell bodies and IR varicosities was reduced (d; P = 0.026, n = 8, unpaired t-test).