18 Questions
What is the primary function of a ligand in pharmacodynamics?
To selectively attach to particular receptors and produce a biological effect
What is the term used to describe a drug that interacts with a single type of receptor expressed on only a limited number of differentiated cells?
Specificity
Which of the following receptors is characterized by a 7-transmembrane domain on the cell membrane?
G protein-coupled receptors
What is the term used to describe the capacity of a drug to induce a functional change or activation of a receptor?
Intrinsic activity
What is the result of stimulation of the nicotinic receptor by acetylcholine?
Sodium influx and potassium outflux
What is the primary difference between an agonist and a partial agonist?
The ability to increase the fraction of R*
What is the term used to describe the magnitude of the response to a drug?
Proportional to the number of drug-receptor complexes
What is the primary function of an antagonist in pharmacodynamics?
To occupy the receptor but not increase the fraction of R*
What is the term used to describe receptors that are expressed on the cell membrane and sense the external environment?
G protein-coupled receptors
What is the term used to describe a receptor that is activated by an agonist, which opens the channel briefly for a few milliseconds?
Ligand-gated ion channels
What is the primary effect of an antagonist on the receptor?
It stabilizes the receptor in the inactive state.
Which type of receptor is characterized by the brief opening of a channel when activated by an agonist?
Ligand-gated ion channel receptor
What is the primary difference between a full agonist and a partial agonist?
The efficacy of the drug in producing a response
What determines the magnitude of the response to a drug?
The number of drug-receptor complexes
What is the primary characteristic of a receptor with high specificity?
It interacts with a single type of receptor expressed on only a limited number of differentiated cells
What is the primary function of a G protein-coupled receptor?
To sense the external environment
What is the primary effect of a partial agonist on the receptor?
It causes a smaller increase in the fraction of R* compared to a full agonist
What is the primary characteristic of an intracellular receptor?
It is located in the cytoplasm
Study Notes
Pharmacodynamics
- Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action.
Receptors and Ligands
- A ligand is a molecule that attaches selectively to particular receptors.
- Ligands can be agonists, antagonists, or partial agonists.
Types of Ligands
- Agonists shift the equilibrium from R to R* to produce a biologic effect.
- Antagonists occupy the receptor but do not increase the fraction of R* and may stabilize the receptor in the inactive state.
- Partial agonists cause similar shifts in equilibrium from R to R*, but the fraction of R* is less than that caused by an agonist.
Intrinsic Activity and Specificity
- Intrinsic activity or efficacy is the capacity to induce a functional change or activation of the receptor.
- Specificity refers to a drug that interacts with a single type of receptor expressed on only a limited number of differentiated cells.
Drug-Receptor Complex
- The magnitude of the response is proportional to the number of drug-receptor complexes.
Major Receptor Families
- Ligand-gated ion channels receptors: the channel is usually closed until the receptor is activated by an agonist, which opens the channel briefly.
- G protein–coupled receptors (GPCR): 7 transmembrane domain receptors on the cell membrane that sense the external environment.
- Enzyme-linked receptors.
- Intracellular receptors.
Pharmacodynamics
- Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action.
Receptors and Ligands
- A ligand is a molecule that attaches selectively to particular receptors.
- Ligands can be agonists, antagonists, or partial agonists.
Types of Ligands
- Agonists shift the equilibrium from R to R* to produce a biologic effect.
- Antagonists occupy the receptor but do not increase the fraction of R* and may stabilize the receptor in the inactive state.
- Partial agonists cause similar shifts in equilibrium from R to R*, but the fraction of R* is less than that caused by an agonist.
Intrinsic Activity and Specificity
- Intrinsic activity or efficacy is the capacity to induce a functional change or activation of the receptor.
- Specificity refers to a drug that interacts with a single type of receptor expressed on only a limited number of differentiated cells.
Drug-Receptor Complex
- The magnitude of the response is proportional to the number of drug-receptor complexes.
Major Receptor Families
- Ligand-gated ion channels receptors: the channel is usually closed until the receptor is activated by an agonist, which opens the channel briefly.
- G protein–coupled receptors (GPCR): 7 transmembrane domain receptors on the cell membrane that sense the external environment.
- Enzyme-linked receptors.
- Intracellular receptors.
This quiz covers the study of pharmacodynamics, including the biochemical and physiological effects of drugs, their mechanisms of action, and the role of ligands and antagonists in producing biological effects.
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