1931年Von Euler和Gaddum从马脑和小肠中提取出P物质(SP)

半个世纪以来

对其生理药理作用进行了大量研究

证明P物质是一种重要的肽类神经递质

特别是在痛觉调制中起重要作用。在脊髓背角和三叉神经核中

P物质可能是初级神经元传递“疼痛信息”的物质

但在中枢神经系统(CNS)不同部位作用的特异性及其在针刺镇痛中的意义

尚未见系统报The latency of avoidance response induced by radiant heat applied on the snout or tail was taken as the pain threshold. The injection of substance P(SP

2.5 or 5μg) through the implanted cannulae into the periaqueductal gray matter (PAG) produced a dose-dependent analgesic effect

the pain threshold being increased by 59±9% and 91±18%

respectively. Injected into the subarachnoid space of spinal cord

SP induced a lowering of the pain threshold dy 26±6% from the basal. Antidody microinjection study revealed that intra-PAG injection of anti body directed to SP significantly attenuated the analgesic effect of electroacupuncture (EA). In contrast

intrathecal injection of SP antibody apparently enhanced the EA analgesia. These results suggest that in the brain and in the spinal cord of the rabbit SP may display opposite effects: potentiation of EA analgesia in PAG and antagonism of EA effect in the spinal cord.