Otto Loewi Won a Noble Prize in 1936 for Showing

Short Answer

Otto Loewi won a Noble Prize in 1936 for showing that nerves release chemical transmitters. For one of his experiments he showed that stimulating the vagus nerve caused the heartbeat to slow down. He then collected the 'releasate' from nerve stimulation and put it on another heart, in which the heartbeat slowed as well. The substance that was release was later identified as ACh. What do we know now about the mechanism by which ACh decreases heart rate? Fill in the blanks in the following sentence.
ACh binds to the _____ cholinergic receptor, which activates a specific G protein, ____. This causes the dissociation of the trimeric G protein complex and the _____subunits bind to and activate a class of channels called _______, which OPEN/CLOSE (choose one) and result in ______ions moving INTO/OUT (choose one) of the cell. This DEPOLARIZES/HYPERPOLARIZES (choose one) the muscle cells, slowing the heartbeat.