Substance P (SP) is an endogenous tachykinin neuropeptide that is involved in inflammatory, pain, and stress signaling; it exhibits neuroprotective, cognition enhancing, and gastrointestinal motility modulating activities. SP exhibits neuroprotective activity by decreasing expression of Kv1.4 K+ channels in transgenic animal models of Alzheimer’s disease and improving cognitive performance in the Morris water maze task. SP is the natural ligand for the neurokinin-1 (NK1) receptor.