Pharmacology
Receptor
A receptor is a protein molecule on or within a cell that binds specific molecules (ligands) and triggers a cellular response, mediating the effects of peptides and drugs.
Detailed Explanation
Receptors are the primary targets of most peptide therapeutics. They can be membrane-bound (G-protein-coupled receptors, receptor tyrosine kinases) or intracellular (nuclear receptors). When a peptide binds its receptor, it activates signaling cascades that produce the biological effect. Examples include the ghrelin receptor (GHS-R1a) targeted by GHRPs and the GLP-1 receptor targeted by Semaglutide.