HCN2 and type 2 diabetes mellitus: Hyperactivated HCN2 in Na(v)1.8 positive neurons drive pain in mouse models of diabetic neuropathy and inhibition of HCN2 alleviates pain in both type 1 and type 2 diabetes mouse models (Figure 9).[198] In addition to hyperalgesia, diabetic neuropathy also involves mechanical allodynia and small fiber degeneration.