摘要
Since the successful extraction of substance P (SP) was carried out by Von Euler in 1931, its physiological role is still not well known. The actions of SP in different parts of the CNS are quite different. For example, SP in the dorsal horn of the spinal cord may act as the mediator of 'pain' signals, whereas in the brain it may have an analgesic effect. Because of the different results obtained from the
