Substance P and the neurokinins: novel peptide neurotransmitters in psychopharmacology.

A new neurotransmitter system is a family of 3 related peptides known as neurokinins. The best known of these is substance P. The others are known simply as neurokinin A and neurokinin B. The specific receptor subtypes that correspond to these 3 neurokinins are neurokinin 1 receptors for substance P, neurokinin 2 receptors for neurokinin A, and neurokinin 3 receptors for neurokinin B. These neurotransmitters appear to play a key role in the regulation of emotions, and antagonists of their receptors may be novel psychotropic drugs of the future.