Receptor Pharmacology and Drug Interactions

Vocabulary flashcards covering foundational concepts of receptor pharmacology, including agonists, antagonists, kinetic parameters, affinity, efficacy, and binding sites.

Agonist

An agent that binds to a receptor and produces an intracellular response, mimicking or enhancing the action of an endogenous ligand.

Antagonist

An agent that binds to a receptor but does not result in receptor activation, occupying the receptor to prevent activation by other ligands.

Albuterol

A beta two adrenergic receptor agonist that binds to beta two receptors in airway smooth muscle and activates them, leading to bronchodilation.

Propranolol

A beta receptor antagonist that binds beta receptors and prevents epinephrine and norepinephrine from activating them, lowering heart rate and blood pressure.

Morphine

A drug that acts as a full agonist at mu opioid receptors and produces analgesia.

Naloxone

An opioid receptor antagonist that blocks opioid receptors and reverses opioid toxicity.

Lock and Key Model

A simplified model visualizing receptor binding where the receptor acts as the lock and the drug or ligand acts as the key.

Association Rate Constant ($k_{on}$)

A rate constant describing how quickly a drug associates with or binds to a receptor.

Dissociation Rate Constant ($k_{off}$)

A rate constant describing how quickly a drug dissociates from or leaves a receptor.

Pharmacodynamics

The branch of pharmacology that addresses the question of what the drug does to the body, including drug-receptor interactions.

Pharmacokinetics

The branch of pharmacology that addresses the question of what the body does to the drug, including clearance, metabolism, half-life, and tissue accumulation.

Affinity

The strength of drug receptor binding, determined by how tightly and persistently a drug binds to a receptor.

Equilibrium Dissociation Constant ($K_d$)

A measure of affinity defined by the equation $K_d = \frac{k_{off}}{k_{on}}$, where a lower $K_d$ value indicates higher affinity.

Selectivity

The property describing whether a drug binds preferentially to one receptor or receptor subtype over others.

Intrinsic Efficacy

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

Full Agonist

A drug with high intrinsic efficacy that produces the maximal response the system is capable of producing.

Partial Agonist

A drug with lower intrinsic efficacy that produces a submaximal response even when fully occupying the receptor.

Buprenorphine

A partial agonist at mu opioid receptors that produces submaximal activation compared to full agonists.

Orthosteric Site

The traditional ligand binding site of a receptor where the endogenous ligand normally binds.

Allosteric Site

A binding site on a receptor that is distinct from the orthosteric site.

Allosteric Modulators

Drugs that bind to allosteric sites and modify receptor behavior by changing receptor conformation.

Positive Allosteric Modulators

Allosteric modulators that increase receptor activity.

Negative Allosteric Modulators

Allosteric modulators that reduce receptor activity.

Benzodiazepines

A class of drugs that bind to an allosteric site on the GABA a receptor and enhance the effect of GABA.