Pharmacodynamics

Receptor

TRReseptör
Also known as:Drug receptor

A macromolecule, usually a protein, to which a drug or endogenous ligand binds specifically and thereby initiates a change in cell function that produces a biological response.

In depth

Four main receptor superfamilies are recognised: ligand-gated ion channels (responses within milliseconds), G protein-coupled receptors (seconds), kinase-linked receptors such as receptor tyrosine kinases, and nuclear receptors that regulate gene transcription (hours). Receptors have two functions: recognition of the ligand (binding, governed by affinity) and transduction of binding into a cellular response (related to efficacy).

In a broader sense, enzymes, transporters, voltage-gated ion channels and structural proteins are also drug targets. Receptor number and responsiveness are not fixed; they change with disease and with prolonged exposure to agonists or antagonists.

Clinical pearl

Chronic β-blockade up-regulates β-adrenoceptors, so abrupt withdrawal can provoke rebound tachycardia, angina or arrhythmia; β-blockers should be tapered rather than stopped suddenly.

TRIn Turkish

Reseptör

Bir ilacın veya endojen ligandın özgül olarak bağlandığı ve bu bağlanma aracılığıyla hücre işlevinde değişiklik başlatarak biyolojik yanıt oluşturan, genellikle protein yapısındaki makromoleküldür.

Dört ana reseptör üst ailesi tanımlanır: ligand kapılı iyon kanalları (milisaniyeler içinde yanıt), G proteinine kenetli reseptörler (saniyeler), reseptör tirozin kinazlar gibi kinaz bağlantılı reseptörler ve gen transkripsiyonunu düzenleyen nükleer reseptörler (saatler). Reseptörlerin iki işlevi vardır: ligandın tanınması (afiniteyle belirlenen bağlanma) ve bağlanmanın hücresel yanıta dönüştürülmesi (etkinlikle ilişkili sinyal iletimi).

Daha geniş anlamda enzimler, taşıyıcılar, voltaj kapılı iyon kanalları ve yapısal proteinler de ilaç hedefleridir. Reseptör sayısı ve duyarlılığı sabit değildir; hastalıkla ve agonist ya da antagonistlere uzun süreli maruziyetle değişir.

Uzun süreli β-blokaj β-adrenerjik reseptörlerin up-regülasyonuna yol açar; bu nedenle ani kesilme rebound taşikardi, anjina veya aritmiye neden olabilir ve β-blokerler birden kesilmek yerine azaltılarak bırakılmalıdır.

Diğer adları:İlaç reseptörü
Updated 24.09.2026 1 views Educational reference — verify against current sources before clinical use.

Read next

LigandLigand

Any molecule, such as a drug, hormone or neurotransmitter, that binds to a specific site on a receptor or other macromolecule; binding alone does not imply activation or blockade.

 G Protein-Coupled ReceptorG Proteinine Kenetli Reseptör

A member of the largest family of cell-surface receptors, a single polypeptide with seven transmembrane α-helices that transduces ligand binding into intracellular signals by activating heterotrimeric G proteins.

 Ligand-Gated Ion ChannelLigand Kapılı İyon Kanalı

A transmembrane ion channel that opens (or, less often, closes) directly when a specific ligand, usually a neurotransmitter, binds to it, producing rapid changes in membrane potential within milliseconds.

 AffinityAfinite

The strength of binding between a drug and its receptor or target, determined by the rates of association and dissociation and usually expressed as the equilibrium dissociation constant (Kd) or its negative logarithm (pKd).

 AgonistAgonist

A drug or endogenous substance that binds to a receptor and activates it, producing a biological response; it possesses both affinity and efficacy (intrinsic activity).

 AntagonistAntagonist

A drug that binds to a receptor or other target without activating it (affinity but no efficacy) and thereby prevents or reduces the response to an agonist.