Substance P: A new era, a new role

Substance P has been extensively studied and is considered the prototypic n europeptide of the more than 50 known neuroactive molecules. The understand ing of substance P has evolved beyond the original concept as the pain tran smitter of the dorsal horn. Animal and genetic research, recent development s of nonpeptide substance P antagonists, and important changes in the under standing of neuro transmission have each contributed to the current underst anding of substance P. After 7 decades, the physiologic role of substance P is known as a modulator of nociception, involved in signaling the intensit y of noxious or aversive stimuli. Genetic studies in mice and development o f substance P antagonists provide more recent results that support the rede finition of the central role of substance P. Evidence suggests that this ne uropeptide is an integral part of central nervous system pathways involved in psychologic stress.