The term "blockers" refers to substances or compounds that interfere with the activity of specific receptors, channels, enzymes, or other molecular targets in biological systems. They inhibit the normal function of the target, modulating physiological processes or biochemical reactions. Receptor blockers, also known as antagonists, bind to specific receptors on cells or in tissues without activating them. Channel blockers inhibit the flow of ions (such as sodium, potassium, calcium, or chloride ions) through ion channels in cell membranes. Enzyme blockers inhibit the activity of specific enzymes by binding to their active sites or other functional regions. Transporter blockers interfere with the function of membrane transport proteins responsible for transporting molecules or ions across cell membranes.