Data computational model parameters of nociceptive medullary dorsal horn projection neuron from: Opposite regulation of medullary pain-related projection neuron excitability in acute and chronic pain

Pain hypersensitivity is associated with increased activity of peripheral
and central neurons along the pain neuroaxis. We show that at the peak of
acute inflammatory pain, superficial medullary dorsal horn projection
neurons (PNs) that relay nociceptive information to the parabrachial
nucleus reduce their intrinsic excitability and, consequently, action
potential firing. When pain resolves, the excitability of these neurons
returns to baseline. Using electrophysiological and computational
approaches, we found that an increase in potassium A-current (IA)
underlies the decrease in the excitability of medullary dorsal horn PNs in
acute pain conditions. In chronic pain conditions, no changes of IA were
observed, and medullary dorsal horn PNs exhibit increased intrinsic
excitability and firing. Our results reveal an opposite modulation of the
excitability of medullary dorsal horn projection neurons in acute and
chronic pain conditions, suggesting a regulatory mechanism that, in acute
pain conditions, fine tunes the output from the dorsal horn network and,
if lacking, could facilitate pain chronification.