What Is The Lock And Key Analogy For Neurotransmitters?

What Is The Lock And Key Analogy For Neurotransmitters? In the lock-and-key analogy for neurotransmitters, the lock refers to the post-synaptic receptors, whereas the key refers to the shape of the neurotransmitter. What is the role of the lock and key system as it relates to neurotransmitters? Receptors and neurotransmitters act like a lock-and-key system.