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The term neurotransmitter is given to the endogenously produced chemical molecules which are functionally involved in transmitting neural signals to the target tissue. A neurotransmitter carries instructions for the postsynaptic end of the synapse, and it is released by the presynaptic terminals.

In neurophysiology and biochemistry, a receptor can be defined as proteinaceous cellular components thatfacilitate the transmission of signals from neuronal cells to the target cells. A receptor can be of various types, such as ion-gated receptors, G-protein receptors, and enzyme-gated receptors.

Generally, different cells have different receptors, and a single neurotransmitter molecule has the ability to bind with different types of receptors. According to the type of receptor, the response generated by the neurotransmitter is different on different target tissues.

The role of receptors on neurotransmitter response can be explained through the different effects of acetylcholine (a neurotransmitter). When acetylcholine binds with the ion-gated receptors present on the surface of skeletal muscles, it generates a stimulating effect and causes muscular contraction.

In contrast, when acetylcholine binds with the G-protein receptors present on the cardiac muscles, it generates an inhibitory effect and decreases the heart’s contraction.