Atropine and curare
Atropine acts by preventing acetylcholine from depolarization of the post synaptic membrane and also prevents the generation of impulse in the cell. Curare can produce similar effect but it targets the junction between the nerve cells and muscles. Curare was derived from the plants in central ans south America. This can cause muscle weakness and death by asphyxiation at high doses due to paralysis of the diagphragm.