40 Questions
What is the primary focus of clinical pharmacology?
The study of the complex interaction between the drug and the patient
What is a drug, according to the definition?
A chemical molecule that can interact with the body at the molecular level
What is the main focus of pharmacodynamics?
What the drug does to the body
Which of the following is NOT a mechanism of drug action?
Electromagnetic interaction
What is a receptor in the context of pharmacodynamics?
A molecule that interacts with a drug to produce a response
What is the primary focus of medical pharmacology?
The science of dealing with small molecules used to prevent, diagnose, or treat diseases
Which of the following is an example of a direct chemical or physical mechanism of drug action?
Binding to a DNA molecule
What is the interaction between the drug and the patient in clinical pharmacology?
A complex interaction that involves the rational, safe, and effective use of drugs
What is the role of a ligand that blocks the receptor?
to inactivate the receptor
What determines the number of receptors occupied by a drug?
the affinity of the receptor
What is characteristic of the response of ion channel-linked receptors?
it is fast and short-lasting
What is the function of an agonist?
to activate the receptor
What is the composition of an ion channel-linked receptor?
a complex of multiple subunits
What happens when an agonist binds to the extracellular part of an ion channel-linked receptor?
the channel opens
What is the role of affinity in the receptor-ligand interaction?
it determines the number of receptors occupied by the ligand
What is the term for the molecule that combines with a receptor?
ligand
Which type of receptors are located in the motor end plate and respond to nicotinic Ach?
Ion channel receptors
What is the response of GABA receptors in the brain to stimulation?
The ion channel opens for Cl- ions
What is the general structure of G-protein-linked receptors?
Consists of 7 transmembrane subunits
What is the effect of G-protein activation on GTP?
It binds to GTP to be phosphorylated
What is the consequence of stimulatory G-protein activation?
Increase in cAMP levels
Which of the following receptors are examples of Gs-coupled receptors?
Beta1 and beta2-adrenergic receptors
What is the effect of ion channel receptors compared to G-protein-linked receptors?
Ion channel receptors are faster and shorter-lasting
What is the consequence of binding of an agonist to the extracellular part of a G-protein-linked receptor?
Activation of the intra cellular G-protein
What is the effect of inhibitory G-protein (Gi) on adenyl cyclase enzyme?
It decreases cAMP
What is the effect of Gq-coupled receptors on inositol triphosphate (IP3)?
It increases IP3
What is the function of the TK-binding domain in tyrosine kinase (TK)-linked receptors?
It binds to tyrosine kinase
Which of the following receptors is NOT an example of a Gi-coupled receptor?
α1-adrenergic receptor
What is the effect of IP3 on free intracellular Ca2+?
It increases free intracellular Ca2+
Which domain of the tyrosine kinase (TK)-linked receptor binds to hormones?
Extracellular hormone-binding domain
What is the effect of Gi-coupled receptors on protein kinases?
It inhibits protein kinases
What is the function of the transmembrane segment in tyrosine kinase (TK)-linked receptors?
It connects the extracellular and intracellular domains
What happens when an agonist binds to the hormone-binding domain of a receptor?
Activation of TK enzyme
Where are intracellular receptors located?
Inside the cell, either in the cytoplasm or directly on the DNA
What is a characteristic of intracellular receptors?
Their response is slow and their effects persist for a long time
What type of bond is strong and irreversible?
Covalent bond
What is the role of signaling proteins in the signaling pathway?
To activate several proteins in the signaling pathway
What must happen for an agonist to bind to an intracellular receptor?
The agonist must enter the cell to reach the receptor
What is an example of a receptor that is an intracellular receptor?
Corticosteroid receptor
What is the characteristic of an ionic bond?
It is an electric attraction between two opposing charges
Study Notes
Medical Pharmacology
- Medical pharmacology is a basic science that deals with small molecules used to prevent, diagnose, or treat diseases.
- Clinical pharmacology is the science concerned with the rational, safe, and effective use of drugs in humans.
Pharmacodynamics
- Pharmacodynamics is the study of what a drug does to the body.
- A drug can produce its effects through:
- Interaction with body control systems (regulatory proteins)
- Direct chemical or physical mechanisms
- Interaction with certain metabolic pathways
Receptors
- Receptors are protein macromolecules that combine with a drug to produce an effect.
- Ligand: any molecule that can combine with receptors.
- Agonist: a ligand that activates the receptor.
- Antagonist: a ligand that blocks the receptor.
- Affinity: the empathy of the receptor to the ligand, determining the number of receptors occupied by the drug.
Types of Receptors
-
Ion channel-linked receptors (direct ligand-gated ion channels):
- The receptor is an ion channel consisting of 5 transmembrane subunits.
- Binding of the agonist to the extracellular part of the receptor causes opening of the channel for a specific ion.
- Examples: nicotinic Ach receptors in the motor end-plate, GABA receptors in the brain.
-
G-protein-linked receptors:
- The receptor consists of 7 membrane subunits.
- Binding of the agonist to the extracellular part of the receptor causes activation of intracellular G-protein.
- Examples: stimulatory G-protein (Gs) leads to increase in adenyl cyclase enzyme → ↑ cAMP, inhibitory G-protein (Gi) leads to decrease in adenyl cyclase enzyme → ↓ cAMP.
-
Gq-coupled receptors:
- They increase inositol triphosphate (IP3) and diacylglycerol (DAG).
- IP3 increases free intracellular Ca.
- Examples: α1-adrenergic receptors, M1 and M3 muscarinic receptors.
-
Tyrosine kinase (TK)-linked receptors:
- The receptor consists of 2 large domains: an extracellular hormone-binding domain and an intracellular TK-binding domain.
- Binding of the agonist to the hormone-binding domain causes activation of the intracellular domain to activate TK enzyme.
- Examples: insulin receptors.
-
Intracellular receptors:
- They are located inside the cell, either in the cytoplasm or directly on the DNA.
- They regulate transcription of genes in the nucleus or the mitochondria.
- Examples: receptors for corticosteroids, sex hormones, thyroxin, etc.
Types of Drug-Receptor Bonds
-
Ionic bond:
- Electric attraction between two opposing charges.
- Strong but reversible.
-
Hydrogen bond:
- Attraction between two hydrogen bonds.
- Weak and reversible.
-
Covalent bond:
- Very strong and irreversible.
Learn about medical pharmacology, clinical pharmacology, and pharmacodynamics, including the effects of drugs on the body and their mechanisms.
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