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Lecture

Pharmacodynamics: Ligand-Receptor Interactions and Drug Effects

Description

This lecture covers the quantitative description of ligand-receptor binding, including equilibrium binding, association/dissociation kinetics, and concentration-effect relationships. It explores agonists, antagonists, and allosteric modulators, such as benzodiazepines, affecting receptor responsiveness. The lecture delves into the mechanisms of GABAA receptor modulators and the pharmacology of nicotinic acetylcholine receptors. It discusses competitive and non-competitive inhibition, binding/activation stoichiometry, and the variability of drug responses. Additionally, it explains desensitization, tachyphylaxis, and factors influencing drug response, like receptor internalization and altered drug metabolism.

Official source

Ontological neighbourhood

Health sciences

Pharmacology: Drug discovery

Biology

Cell biology: Receptors

Related concepts (32)

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of receptor proteins. They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers. In pharmacology, antagonists have affinity but no efficacy for their cognate receptors, and binding will disrupt the interaction and inhibit the function of an agonist or inverse agonist at receptors.

Receptor (biochemistry)

In biochemistry and pharmacology, receptors are chemical structures, composed of protein, that receive and transduce signals that may be integrated into biological systems. These signals are typically chemical messengers which bind to a receptor and produce physiological responses such as change in the electrical activity of a cell. For example, GABA, an inhibitory neurotransmitter inhibits electrical activity of neurons by binding to GABA_A receptors.

Allosteric modulator

In pharmacology and biochemistry, allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimuli. Some of them, like benzodiazepines or alcoholic beverages, function as psychoactive drugs. The site that an allosteric modulator binds to (i.e., an allosteric site) is not the same one to which an endogenous agonist of the receptor would bind (i.e., an orthosteric site). Modulators and agonists can both be called receptor ligands.

Inverse agonist

In pharmacology, an inverse agonist is a drug that binds to the same receptor as an agonist but induces a pharmacological response opposite to that of the agonist. A neutral antagonist has no activity in the absence of an agonist or inverse agonist but can block the activity of either; they are in fact sometimes called blockers (examples include alpha blockers, beta blockers, and calcium channel blockers). Inverse agonists have opposite actions to those of agonists but the effects of both of these can be blocked by antagonists.

Nicotinic agonist

A nicotinic agonist is a drug that mimics the action of acetylcholine (ACh) at nicotinic acetylcholine receptors (nAChRs). The nAChR is named for its affinity for nicotine. Examples include nicotine (by definition), acetylcholine (the endogenous agonist of nAChRs), choline, epibatidine, lobeline, varenicline and cytisine. Nicotine has been known for centuries for its intoxicating effect. It was first isolated in 1828 from the tobacco plant by German chemists Posselt and Reimann.

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Pharmacodynamics exercises

Covers the analysis of binding measurements and toxin kinetics in pharmacodynamics.

Pharmacodynamics: Ligand-Receptor Binding Kinetics