The Development of Receptor Theory John Newport Langley(1852-1926),a British physiologist, first coined the term"receptive substance".His work described curare as a blocker of neuromuscular transmission,as he was able to show that curare also could block chemical stimulation of frog gastrocnemius muscle by nicotine,without motor nerves.Therefore, there is a mutual antagonism between nicotine and curare,and the effect of which depends on the relative concentration of each.He also worked on atropine and pilocarpine,and the work led to the hypothesis that both atropine and pilocarpine could form a complex with a common substance at the nerve end,which we now know are the muscarinic receptors. The Development of Receptor Theory Langley's work also led to the concept that the rate of combination(binding)and the saturable effects are characteristic of drug and receptor interactions.This concept was not readily accepted at that time.For instance,Henry H.Dale(1875-1968)thought that the differential effectiveness of adrenaline analogues in mimicking sympathetic functions in varying tissues does not necessarily imply the existence of specific chemical receptors on target tissues.Eventually, experimental data prove the presence of specific receptors for these (as we know today) pharmacological interactions.The Development of Receptor Theory John Newport Langley (1852-1926), a British physiologist, first coined the term “receptive substance”. His work described curare as a blocker of neuromuscular transmission, as he was able to show that curare also could block chemical stimulation of frog gastrocnemius muscle by nicotine, without motor nerves. Therefore, there is a mutual antagonism between nicotine and curare, and the effect of which depends on the relative concentration of each. He also worked on atropine and pilocarpine, and the work led to the hypothesis that both atropine and pilocarpine could form a complex with a common substance at the nerve end, which we now know are the muscarinic receptors. The Development of Receptor Theory Langley’s work also led to the concept that the rate of combination (binding) and the saturable effects are characteristic of drug and receptor interactions. This concept was not readily accepted at that time. For instance, Henry H. Dale (1875-1968) thought that the differential effectiveness of adrenaline analogues in mimicking sympathetic functions in varying tissues does not necessarily imply the existence of specific chemical receptors on target tissues. Eventually, experimental data prove the presence of specific receptors for these (as we know today) pharmacological interactions