A developmental influence of substance P on its receptors.

Events which alter the chemical environment of the developing nervous system have long-term consequences for neural function and behavior. Neonatal exposure to a peptide neurotransmitter, substance P (SP), increased the number of SP binding sites in the adult rat salivary glands, without altering their affinity. The neonatal treatment also increased the binding capacity for SP of several brain regions, but had no effect on SP levels in the brain. The increase in SP binding sites may be responsible for increases in sensitivity to SP in adults after neonatal treatment with the peptide.