Compounds that inhibit receptors by preventing the natural messenger from binding are known as

Compounds that inhibit receptors by preventing the natural messenger from binding are known as antagonist.    

 Antagonists are molecules that will block the binding of the natural messenger at a receptor molecule. As a result, the signal which is usually produced by a receptor-messenger coupling will be inhibited. An antagonist can be a drug that blocks a biological response by binding to and blocking a receptor.