Receptor
A receptor is a protein on or inside a cell that receives chemical signals. A molecule with the right shape can bind to it, the way a key fits a lock, and that binding tells the cell to do something.
Where the word comes from
Receptor is Latin: receptor, “one who receives,” from the verb recipere, “to receive.” The scientific idea is about as old as the word’s use in biology. Around the start of the 1900s, pharmacologists — Paul Ehrlich and John Langley among them — proposed that drugs act by attaching to specific “receptive substances” on cells. Decades later, biochemists isolated those substances and showed they are proteins, which is the modern meaning.
What it means here
Much of the published research on peptides is really research on receptors: which receptor a peptide binds, how tightly, and what the cell does after the binding happens. A peptide that binds one receptor and ignores its close relatives is called selective, and selectivity is one of the main things laboratory studies measure. When a product page here names a receptor — a melanocortin receptor, a growth-hormone secretagogue receptor — it is describing this lock-and-key relationship as reported in published studies, not describing an effect in a person.
Words you’ll see together
- binding affinity — how tightly a molecule holds onto its receptor
- nM — nanomolar, the concentration unit affinity is usually reported in
- ligand — the general word for any molecule that binds a receptor
- selectivity — how much a molecule prefers one receptor over its relatives
- subtype — one member of a receptor family, such as MC4R among melanocortin receptors
Related terms
- Agonist — a molecule that binds a receptor and switches it on
- Melanocortin receptor — a receptor family that appears often in this catalog’s research
- Peptide — the kind of molecule whose shape does the binding
Where it appears in our catalog
- Ipamorelin — described in a 1998 paper as the first selective compound of its receptor class
- PT-141 — studied at several melanocortin receptors in published work
- VIP — a peptide whose own named receptors (VPAC/VIPR) are active research subjects
References
- Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH (1998). Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 139(5):552-561. PMID 9849822
- Bardhan M et al. (2025). MC1R/MC3R/MC4R polymorphisms modulate bremelanotide response variability. Diseases. PMID 41002740
