Curare is a poisonous plant extract. Curare molecules have a chemical structure like the neurotransmitter ACh. Curare can bind to the ACh receptor site on the chemically gated ion channels in the motor end plate. Even though curare will bind to the receptor site it will not open the ion channel and no ions will pass through. 1. What do you think the symptoms of curare poisoning would look like? A. Curare is a poisonous plant extract. B. Curare molecules have a chemical structure like the neurotransmitter ACh. C. Curare can bind to the ACh receptor site on the chemically gated ion channels in the motor end plate. D. Even though curare will bind to the receptor site it will not open the ion channel and no ions will pass through. 2. What do you think the symptoms of curare poisoning would look like? A. Muscles will respond too quickly and cause a severe tremor. B. Curare will only affect muscles with ACh receptors, paralyzing them. C. Smooth muscles will become stimulated causing quick movement of nutrients through the digestive system. D. Curare will only affect cardiac muscle, causing fibrillations of the heart.

Acetylcholine receptors are located on the surface of muscle cells, especially in the synapse between muscle cells and nerve cells. Muscles are constantly pumping sodium out of their cells, so, when they are relaxed, there is more sodium outside than inside. When they get the signal from the nerve, the channels open and sodium ions get back inside, starting the process muscle contraction. IF curare binds to the site where Acetylcholine is supposed to act, and thus blocking all this muscle contraction signal, it will produce a progressive paralysis of all muscles.