What are molecules that bind to cell receptors and trigger a response called?

Molecules that bind to cell receptors and trigger a response are known as agonists. Agonists activate receptors and lead to a physiological response in the cell, mimicking the action of naturally occurring substances in the body. This function is essential in pharmacology where drugs are designed to activate particular receptors to produce desired effects, such as alleviating symptoms or enhancing certain bodily functions.

In contrast, antagonists are molecules that bind to the same receptors but do not trigger a response; instead, they block or dampen the effects of agonists. Enzymes, on the other hand, are biological catalysts that facilitate biochemical reactions but do not specifically engage with receptors to produce a cellular response. Inhibitors typically refer to molecules that decrease the activity of enzymes or receptors, not activating them. Thus, agonists are specifically responsible for inducing a response when they bind to receptors.