411 Section 2: Drug Receptors FLASHCARDS

Ligand

A substance that forms a complex with a biomolecule to serve a biological purpose; it alters receptor conformation and function.

Receptor

A cell component where a drug or hormone binds to initiate biochemical events, causing a conformational change and altered cellular function.

Ion Channel Receptors

Receptors that span the membrane and form an ion channel pore upon ligand binding, increasing membrane permeability to specific ions.

Enzyme-Linked Receptors

Surface receptors with an extracellular binding site and an intracellular catalytic domain that activate enzymatic activity upon ligand binding.

G Protein-Coupled Receptors (GPCRs)

Surface receptors that engage intracellular regulatory G proteins upon ligand binding, affecting downstream signaling and second messenger generation.

Second Messenger

Small molecules (e.g., cyclic AMP) that act inside the cell to transduce a signal from a receptor to elicit a cellular response.

Affinity

The strength of attraction between a drug and its receptor.

Efficacy

The ability of a bound drug to activate the receptor and produce a cellular response.

Agonist

A drug that binds to a receptor and initiates a metabolic change in the cell.

Antagonist

A drug that binds to a receptor but does not activate it, blocking the action of agonists.

Desensitization

A transient decrease in receptor responsiveness due to overstimulation, often leading to tolerance.

Up-Regulation

An increase in receptor synthesis and sensitivity due to reduced exposure to ligand.

Cholinergic Receptors

Receptors that respond to acetylcholine, including nicotinic and muscarinic subtypes.

Opioid Receptors

Receptors activated by opioids, including mu, kappa, and delta types, involved in pain modulation.

Pharmacodynamics (PD)

The study of the effects of drugs and their mechanisms of action, including how drugs affect the body.

Pharmacokinetics (PK)

The study of how drugs move through the body, including absorption, distribution, metabolism, and excretion.