In the context of preclinical neuropathic pain following peripheral nerve injury, the effects of spinal administration of the irreversible, non-brain penetrant, non-specific inhibitor of CatS; LHVS (morpholinurea-leucine-homophenylalanine-vinyl phenyl sulfone), also indicate that the role of microglial CatS may be more crucial in the maintenance of pain as opposed to the initial induction. The gene discussed is PIMREG; the disease is peripheral nerve injury.