The same ligand can bind to different receptors causing different responses (e.g.. acetylcholine). On the other hand, different ligands binding to different receptors can produce the same cellular response (e.g. glucagon, epinephrine).
In paracrine signaling the signaling molecule affects only target cells in the proximity of the signaling cell. ... Once a signaling molecule binds to its receptor it causes a conformational change in it that results in a cellular response. The same ligand can bind to different receptors causing different responses.
