64 Questions
What term is used to describe the actions of a drug on the body and the influence of drug concentrations on the magnitude of the response?
Pharmacodynamics
In pharmacodynamics, what type of molecules are part of the cascade of events translating agonist binding into a cellular response?
Second messenger or effector molecules
What is a drug termed when it binds to a site on a receptor protein and activates it to initiate a series of reactions?
Agonist
Which type of receptors in cardiac cells bind and respond to acetylcholine?
Muscarinic receptors
What happens when the nicotinic receptor is stimulated by acetylcholine?
Sodium influx and potassium outflux
How do local anesthetics affect the voltage-gated sodium channel?
Inhibit sodium influx
What type of receptors increase chloride influx and hyperpolarization of neurons upon agonist stimulation?
GABA receptors
Which major biological process involves the transcription of DNA into RNA and translation of RNA into proteins?
Protein synthesis
How do ligand-gated ion channels typically behave before being activated by an agonist?
They are closed
What is the typical time course for the activation and response of receptors mentioned in the text?
Hours to days
Which type of receptors exert their action on target cells via intracellular receptors?
G protein-linked receptors
What is a characteristic feature of G protein-linked and enzyme-linked receptors in signal transduction?
Ability to amplify signal intensity and duration
What is the purpose of determining the Therapeutic Index (TI) of a drug?
To establish the effective and toxic dose ranges of the drug
Why are some drugs with low Therapeutic Indices still used to treat serious diseases?
Because the risk of untreated disease outweighs the risk of adverse effects
What happens to patients as the dose of warfarin is gradually increased?
A greater fraction of patients respond as desired until all patients respond
Why is bioavailability critical for drugs with low Therapeutic Indices?
Because it can alter the therapeutic effects significantly
What is the role of the α subunit of a G protein in transmembrane G Protein–Coupled Receptors?
Binds guanosine triphosphate (GTP)
What is the main effect of an agonist binding to a transmembrane G Protein–Coupled Receptor?
Increases GTP binding to the α subunit
Which cellular effector is commonly activated by Gs and inhibited by Gi in transmembrane G Protein–Coupled Receptors?
Adenylyl cyclase
What is the function of the β and γ subunits of a G protein in transmembrane G Protein–Coupled Receptors?
Anchors the G protein in the cell membrane
Which feature characterizes the activation and response of intracellular receptors, such as steroid hormones, as mentioned in the text?
A time course on the order of hours to days
What is potency in the context of pharmacology?
The amount of drug necessary to produce an effect
What is the main target of antimicrobials like trimethoprim, as discussed in the text?
Enzymes
How is potency typically determined in pharmacology?
By using the concentration of drug producing 50% of the maximum effect
Which characteristic of signal transduction is prominent in G protein-linked and enzyme-linked receptors according to the text?
Amplification of signal intensity and duration
What does a Graded Dose-Response Curve show in pharmacology?
The gradual increase in pharmacologic effect with increasing drug concentration
What is a notable mechanism of signal transduction described in the text that protects cells from excessive stimulation?
Signal termination
How does the EC50 for Drugs A and B indicate potency?
Drug A requires less drug to reach 50% effect than Drug B
What term is used to describe the relationship between the dose of a drug and the proportion of a population that responds to it?
Quantal dose-response curve
In pharmacodynamics, what does the Therapeutic Index (TI) of a drug indicate?
The safety of the drug
What does ED50 represent in a quantal dose-response curve?
Drug dose causing a therapeutic response in half the population
How is the therapeutic index (TI) calculated for a drug?
TD50 / ED50
Transmembrane G Protein-Coupled Receptors consist of two protein subunits in the G protein.
False
Binding of an agonist to the receptor decreases GTP binding to the α subunit.
False
The activated effectors produced by Gs and inhibited by Gi generally involve DNA transcription within the cell.
False
Adenylyl cyclase produces the second messenger cyclic adenosine monophosphate (cAMP) upon activation by Gi.
False
Ligand-gated ion channels primarily contain the ligand binding site in the intracellular portion.
False
Membrane-bound proteins are not rich sources of receptors that transduce extracellular signals into intracellular responses.
False
Hydrophilic ligands interact with receptors on the cell surface, while hydrophobic ligands interact with intracellular receptors.
True
Enzymes, nucleic acids, and structural proteins cannot act as receptors for drugs or endogenous agonists.
False
In a quantal dose-response curve, a positive response is defined as a rise of at least 5 mm Hg in systolic blood pressure.
False
Quantal dose-response curves have different shapes compared to log dose-response curves.
False
A drug's Therapeutic Index (TI) is calculated as the ratio of the dose that produces toxicity in half the population (TD50) to the dose that produces a clinically desired response in half the population (ED50).
True
The Therapeutic Index (TI) indicates a drug's efficacy by showing how well it binds to its target receptor.
False
Warfarin is an example of a drug with a large therapeutic index.
False
All patients respond to warfarin at higher doses with no risk of hemorrhage.
False
Bioavailability does not critically alter the therapeutic effects of drugs with low therapeutic indices.
False
The desired response to warfarin is a decrease in the international normalized ratio (INR).
False
Potency is a measure of the drug concentration that produces 100% of the maximum effect.
False
The EC50 value indicates that Drug A is less potent than Drug B.
False
Graded dose-response curves cannot determine drug efficacy and potency.
False
Therapeutic preparations of drugs always reflect their efficacy rather than their potency.
False
Ligand-gated ion channels always contain the ligand binding site in the extracellular portion.
False
G protein–coupled receptors consist of two protein subunits in the G protein.
False
Activation of transmembrane ligand-gated ion channels by an agonist leads to sodium outflux and potassium influx.
False
Local anesthetics bind to the voltage-gated sodium channel, promoting sodium influx and increasing neuronal conduction.
False
Partial agonists like aripiprazole have the ability to stimulate dopaminergic pathways that are overactive.
False
Inverse agonists stabilize the active conformation of receptors when interacting with an agonist.
False
Antagonists can increase the effect of an agonist when present.
False
Inverse agonists have an intrinsic activity greater than zero.
False
In a quantal dose-response curve, a positive response is defined as a rise of at least 5 mm Hg in systolic blood pressure.
False
Adenylyl cyclase produces the second messenger cyclic adenosine monophosphate (cAMP) upon activation by Gi.
False
Quantal dose-response curves have different shapes compared to log dose-response curves.
False
All patients respond to warfarin at higher doses with no risk of hemorrhage.
False
Test your knowledge on the activation and inactivation of factors that influence DNA transcription and protein translation, focusing on intracellular receptors like those of steroid hormones. Explore how different ligands interact with structural proteins, enzymes, RNA, and ribosomes.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
