Pharmacology Quiz Questions for Exam 1

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Jak/Stat Pathway of signal transduction responds to activation by--

Cytokines

In the growth factor kinase cascade, Map (Mitogen-activated protein) kinase acts to phosphorylate--

Transcription Factors

Which second messenger in a G protein coupled receptor signal transduction cascade typically increases intracellular calcium

Inositol triphosphate

Which signal transduction pathway is most important in cell division, growth, and differentiation---

Ras/Raf/ Map Kinase

Coupling of a G protein alpha subunit to an agonist occupied receptor initially leads to

Exchange of bound GDP with GTP

The Nicotinic receptor is an example of a

Ligand gated ion channel

In G protein coupled receptor signal transduction, protein kinase A is typically activated by

Cyclic AMP

An agonist for a ligand gated ion channel typically-

Increases the number of open channels

Diacylgycerol (DAG) produces its intracellular effects by

Activating protein kinase C

Class 1 nuclear receptors that control gene transcription

Bind to hormone response elements of DNA

Myasthenia gravis is a disease in which

Autoantibodies are directed against receptor proteins

Receptors for insulin---

Contain tyrosine kinase in their intracellular domain

Which ion inhibits an enzyme (inositol- 1-phosphatase) in the phosphoinositol cycle---

Lithium

The opening of chloride ion channels by gamma-amino butyric acid is facilitated by--

Benzodiazepine drugs

The most rapid response is produced by activation of

Ionotropic receptors

Which type of receptors contains seven transmembrane helices--

G protein coupled receptors

The treatment of chronic myeloid leukemia with imatinib results from the ability of the drug to inhibit a specific----

Tyrosine kinase

Which receptors are activated by proteolytic cleavage and inactivated by phosphorylation---

Thrombin receptors

Which receptors are entirely located intracellulary---

Thyroid hormone receptors

L (long-lasting)- type calcium channels are correctly described as having--

High activation threshold and slow inactivation

The extrusion of calcium from the cell cytoplasm primarily depends on

The ATP-driven calcium pump

The mechanism by which monamine neurotransmitters are released from nerve terminals is---

Calcium - mediated exocytosis

Batrochotoxin binds sodium channels and thereby ---

Prevents channel inactivation

Closure of potassium channels in excitable membranes causes membrane----

Depolarization

In smooth muscle, inositol triphosphate releases calcium from the ----

Sarcoplasmic reticulum

Calcium facilitates the release of nitric oxide by --

Activating nitric oxide synthase

Amiloride affects epithelial ion transport by blocking---

Sodium channels

In the colon, chloride transport is important in---

Fluid reabsorption

A key step in causing smooth muscle contraction is the phosphorylation of----

Myosin light chain

Adrenergic beta-receptor agonists cause smooth muscle relaxation by---

Increasing cyclic AMP formation

The main problem with all types of bioassay is --

Biological variation

If the dose-response curve of two drugs are parallel in a bioassay, it usually indicated that the two drugs ---

Act on the same type of receptors

Quantal dose-response curves are obtained when studying---

All or nothing responses

Transgenic mice that overexpress mutilated forms of amyloid precursor protein provide a useful model for studying---

Alzheimer's disease

Transgenic animal models referred to as Knock outs---

Result from inactivation of an existing gene

Ch8Concerning the effect of pH on the urinary excretion of drugs, it can be correctly stated that--

Urinary alkalinization accelerates excretion of weak acids

Bioavailability is defined as the proportion of ingested drug that---

Reaches the systemic circulation in an active form.

The rectal route of administration ----

Is suitable for persons with nausea and vomiting

The passage of drugs across the blood-brain barrier

Occurs more readily in the chemoreceptor trigger zone

A calculated volume of distribution greater than total body water is most likely to occur with drugs that are

Highly lipid soluble

Drugs are most readily absorbed across cells of the

Vascular endothelium

The binding of drugs to plasma albumin

Is saturable

Most drugs are absorbed across cell membranes of the gut by the process of

Diffusing through aqueous pores

Which drug is absorbed by a membrane carrier that transports phenylalanine?

Levodopa

Transdermal drug administration

Is not subject to first pass hepatic metabolism

Which is true

A non selective carrier actively transports acidic drugs into the proximal tubule,
A non selective carrier actively transports basic drugs into the proximal tubule.
The un ionized forms of drugs that are weak acids or weak bases undergo passive reabsorption in the proximal tubule.
With an acid filtrate, weak bases tend to remain in the tubule and are excreted.

With an acid filtrate, weak acids will be less ionized and therefore more readily reabsorbed

T/F: Biliary excretion may be the main elimination route for some drugs

True

T/F: The unionized forms of drugs can be excreted in saliva, sweat and tears
Some drugs can be excreted in milk
Drugs may be effectively excreted via the lungs

True

T/F: Biotransformation of drugs commonly inbolves two types of biochemical reactions referred to as phase 1 and phase 2 reactions

True

T/F: Drug metabolism usually renders a drug less lipid soluble and more water solube
The phase 1 reactions include oxidation, reduction and hydrolysis of drugs

True

T/F: The key enxymes in the hepatic microsomal oxidation of drugs are from the cytochrome P450 family
Phase 1 reactions commonsly introduce a reactive group into the drug molecule which serves as a point of attack for a phase 2 reaction
Hydrolytic reactions are not usually catalyzed by hepatic microsomal enzymes

True

T/F: Substituent groups involved in phase 2 reactions include glutathione, glucuronyl, acetyl, sulfate, methyl, glycyl
Virtually all conjugates are pharmacologically inactive

True

T/F: Some drugs eg. Carbamazepine, can increase the metabolism of other drugs by inducing the metabolizing enzymes
Induction of the hepatic microsomal enzymes involves increasing the rate of enzymic reaction
Induction of metabolizing enzymes may enhance the toxicity of parecetamol.

True

T/F: The pharmacological action of some drugs , given orally , is reduced because they undergo first pass metabolism
Some drugs become pharmacologically active only after metabolism

True

Which apply to elimination of drugs from the kidney

Because of pH partition, weak acids are more slowly excreted in alkaline urine, and vice versa.
Several important drugs are removed predominantly by renal excretion, and are liable to cause toxicity in elderly persons and patients w renal disease.

Drug elimination and pharmacokineticsHepatic cytochrome P450 drug metabolizing enzymes are primarily found in ---

The smooth endoplasmic reticulum

Phase 2 drug metabolism usually forms what?

Usually forms inactive metabolites

Ketoconazole produces non-competive inhibition of cytochrome P4450

Binding to the ferric form of heme iron

In the first order drug elimination

The rate of elimination is directly proportional to drug concentration

If a drug is administered repeatedly at the same dose and dosage interval, the time required to reach the steady state plasma drug concentration is proportional to the

Elimination half life

If a drug exhibits saturation (zero order) kinetics , then

The rate of drug elimination is constant

In the two compartment pharmacokinetic model, orally administered drugs are

Distributed from the central to the peripheral compartment

Which of the following will be increased if the rate of drug absorption from the gut is reduced?

Duration of action

The volume of plasma from which a drug is eliminated in a unit of time is known as the

Clearance

Inactive pro drugs have been developed to

Increase drug absorption

** Pharmokinetics--- What does the term first order kinetics mean when applied to the elimination of drug from the body?

It means that the concept of a half life can be applied to the plasma conc of the drug.
-A half life for the drug can be quoted. First order kinetics yields an exponential decline in the plasma conc of drug. In a given time interval the same fraction of the remaining drug will be eliminated.
It predicts that the plasma conc of the drug will decline exponentially.

A drug is infused at 10 mg/min and the plasma conc rises to a steady state of 2 mg/ ml. What is the clearance in ml/min?

5 ml/ min
Clearance = 10 (mg/min)/2(mg/ml) = 5 ml/min
Administration rate= elimination rate
Elimination rate = Css x clearance

At equilibrium, a drug is distributed uniformly in the extracellular fluid, is excreted unchanged by glomerular filtration, and is not reabsorbed. What would be the approx. half life of this drug. Single compartment kinetics are assumed. Assume vol of extracellular fluid is 12 liters and that the glomerular filtration rate is 125 ml. min-1

66 min.
Half life = .693 x vol of distribution / clearance

.693 x 12000 / 125 = 66 minutes

Given the data , what is the patients glomerular filtration rate? Inulin (freely filterd at the glomerulus and is not secreted, reabsorbed or metabolized by tubules) was fiven by intravenous infusion at a constant rate. The following values were obtained----
Plasma steady state conc = 4 mg/l

7.5 l/ h
Clearance = elimination rate / Css

GFR = (300 x .1) / 4 = 7.5 l/h

Ch 12 and 13
Chemical mediators and autonomic nervous syst
Cholerginic The release of Ach from cholinergic nerve terminals is stimulated by

Nitric oxide

Co transmitters released from postganglionic sympathetic neurons include

Adenosine triphosphate
ATP

Constriction of bronchi is typically produced by activation of

Muscarinic M3 receptors

Activation of adrenergic beta-2 receptors produces

Relaxation of the ciliary muscle

The enteric system is primarily concerned with the regulation of

Gastrointestinal motility

The co transmitter known as neuropeptide Y enhances the

Vasoconstrictive effect of norepinephrine

The final step in the release of norepinephrine from sympathetic neurons is

Exocytosis

In the parasympathetic nervous system, neurotransmitter action is terminated by

Enzymatic degredation

The enteric nervous system

Releases several peptide neurotransmitters and
Nitric oxide

Ch 13Activation of muscarinic M2 receptors

Increases potassium conductance

Succinylcholine is characteristically an agonist at

Nicotinic receptors in skeletal muscle

The second messengers formed by activation of muscarinic achtylcholine receptors include

Inositol triphosphate

Pilocarpine lowers intraocular pressure by

Contracting the ciliary muscle

The increased release of potassium from denervated muscles by succinylcholine is due to

Denervation supersensitivity

Edrophonium produces reversible inhibition of cholinersterase by

Binding the anionic site

Pyridostigmine enhances neuromuscular transmission in myasthenia gravis patients by

Inhibiting degradation of acetylcholine

Activation of muscarinic M3 receptors leads to

Exocrine gland secretion

The effects produced by topical ocular administration of atropine include

Mydriasis

If a test dose of edrophonium increases muscle weakness in a myasthenia gravis patient being treated with pyridostigmine, it means that

The dose of pyridostigmine is too high

Atropine poisoning in children typically causes

Hyperthermia

Persons with a genetic variant conferring abnormal plasma cholinesterase activity may exhibit prolonged muscle paralysis following administration of

Succinylcholine

The release of acetylcholine from cholinergic nerve terminals is blocked by

Botulinum toxin

Scopolamine is employed clinically in the prevention or treatment of

Motion sickness

The neuromuscular blockade produced by atracurium can be reversed by administration of

Neostigmine

Transient muscle fasciculations followed by paralysis typically occur after administration of

Succinylcholine

CH 14 Noradrenergic Transmission-(Quest Bank)An intravenous infusion of norepinephrine typically---

Increase peripheral resistance and decrease heart rate

In the liver, epinephrine acts via adrenergic beta-2 receptors to

Stimulate phosphorylase and inhibit glycogen synthase

Which drug inhibits the transport of norepinephrine into synaptic vesicles, thereby leading to neurotransmitter depletion---

Reserpine

Doxazosin is an example of a

Selective alpha-1 adrenoceptor antagonist

Irreversible blockade of alpha-adrenoceptors results from covalent binding of these receptors by----

Phenoxybenzamine

The reuptake of norepinephrine by presynaptic nerve terminals (uptake 1) is inhibited by---

Cocaine

The first-line treatment for acute severe type 1 hypersensitivity reactions is ---

Epinephrine

Which adrenergic receptor antagonist increases heart rate at rest but reduces it during exercise---

Pindolol

In the peripheral tissues, the primary end product of norepinephrine metabolism is ---

Vanillylmandelic acid

The adverse effects of beta-adrenoceptor antogonists include

Bronchoconstriction

Selective beta- 3- adrenoceptor agonists are potentially useful in treating obesity because of their ability to

Increase thermogenesis

Symptoms of urinary retention due to benign prostatic hyperplasia may be improved by --

Alpha- 1 - adrenoceptor antagonists

Persons with acute thyrotoxicosis are often treated with propranolol because it--

Decreases cardiac stimulation

Persons with pheochromocytoma may benefit from administration of methyltyrosine because of its ability to

Inhibit norepinephrine synthesis

Which is main clinically important transmitter at junction of the sympathetic postganglionic neuron with smooth muscle

Noradrenaline- it is the important transmitter released from postganglionic sympathetic nerves

Other facts

Dopamine is a precursor for noradrenaline, and is a neurotransmitter in its own right

Adrenaline is a hormone secreted by the adrenal medulla

Acetylcholine is an important neurotransmitter in peripheral nerves

Which is main clinically important transmitter at the junction of the sympathetic preganglionic neuron with postganglionic neurons

Acetylcholine—is the neurotransmitter in sympathetic ganglia

Which is main clinically important transmitter at the junction of the sympathetic preganglionic neurone with the adrenal medulla

Acetylcholine- These preganglionic fibers, sympathetic in origin, use acetylcholine as the neurotransmitter.

Which is the main clinically important transmitter at the junction of the sympathetic postganglionic neuron with sweat glands?

Acetylcholine- released from postganglionic sympathetic neurons, is the transmitter that acts on sweat glands.

At the junction of the sympathetic postganglionic neuron with smooth muscle which of receptors has clinical importance in terms of being targets for drugs--

Alpha 1 adrenoceptors
And
Beta 2 adrenoceptors

At the junction of the sympathetic postganglionic neuron with sweat glands, which receptor has clinical importance

Muscarinic receptors—responsible for most of the secretory activity of sweat glands. Several useful drugs—Atropine in preanaesthetic meds—are antagonists of acetylcholine at these receptors

Which describe the effect of stimulating alpha 1 adrenoceptors

Contraction of vascular smooth muscle
Stimulation of glycogenolysis
Contraction of the radial muscle of the iris

Which statements describe the effects of stimulating beta adrenoreceptors

All of these are true, false modified to be true!
Beta 2- receptor stimulation relaxes bladder detrusor muscle.
Beta 2 receptor stimulation dilates the bronchioles
Beta 1 receptor stimulation increases the rate and force of the heart beat
Beta 2 receptor stimulation dilates the blood vessels
Beta 2 adrenoceptor stimulation results in glycogenolysis

Describe Beta 2 adrenoreceptors

Beta 2 adrenoreceptors cause relaxation of vascular smooth muscle.
Noradrenaline acting thru beta 2 adrenoceptors relaxes vascular smooth muscle by endothelium dependent nitric oxide release

Describe Beta 1 adrenoreceptors

Noradrenaline acting thru alpha 1 adrenoceptors contracts vascular smooth muscle
Beta 1 adrenoceptors are found mainly in the heart and not on vascular smooth muscle
Stimulation of alpha 1 adrenoceptors causes contraction of vascular smooth muscle
Beta 1 adrenoceptors occur mainly on cardiac muscle.
Noradrenaline acting thru beta 1 adrenoceptors increases the force of contraction of the heart

Describe Beta 3 adrenoreceptors

Beta 3 adrenoceptor mediates responses to catecholamines in adipose tissue, -Lipolysis and thermogenesis, also thermogenesis in skeletal muscle

Describe Alpha 2 adrenoreceptors

Alpha 2 adrenoceptors are found on sympathetic nerve terminals. When activated they decrease transmitter release

Which are important in noradrenaline synthesis

Active uptake of tyrosine into noradrenergic neurons.
Conversion of tyrosine to DOPA—the rate limiting step.

Which is true of the release of noradrenaline from synaptic nerve terminals

The action potential opens volatage gated calcium channels, allowing an influx of calcium- necessary for exocytosis- to the nerve ending

Which is true of the uptake mechanisms of nnoradrenaline—Only true ones are listed

Neuronal uptake involves active transport carrier(the norepinephrine transporter) on the noradrenergic varicosity.
About 75% of the NA released from sympathetic neurons is taken back up into the neuron by Neronal uptake by NET.
The substrate specificity of Neuronal uptake by NET is : NA> adrenaline> Isoproterenol.

Which is true of neuronal uptake—(all true)

Noradrenaline is a substrate - it is taken up into the neuron.
Amphetamine is taken up into the neuron.
Some tricyclic antidepressants (TCAs) are substrates.

Which is true of the enzymatic degradation of noradrenaline shown----

Monamine oxidase (MAO) acts within the varicosity

Which are true of adrenoceptor transduction mechanisms

The main second messenger system for alpha 1 effects involves a rise in intracellular calcium
Activation of presynaptic alpha 2 adrenoceptors results in inhibition of the opening of voltage dependent calcium channels

Which is true of beta adrenoceptor transduction mechanisms in smooth muscle.

Beta 2 adrenoceptors are all coupled to G proteins
The main intracellular messenger system for Beta 2 action is adenylyl cyclase/cyclic AMP
Beta 1 adrenoceptor stimulation in cardiac muscle cells results in increased intracellular calcium

Which is true of clinically useful drugs acting on adrenoceptors--

Phenylephrine is an alpha 1 adrenoceptor agonist.
Propranolol is a Beta 1 antagonist

Which is true of clinical use of adrenoceptor agonists--

Adrenaline(epinephrine) given intramuscularly is used to treat acute anaphylaxis
Salbutamol, given by inhalation is used to treat an asthma attack.

Which is true of adrenoceptor antagonists--

Phenoxybenzamine is a non selective irreversible antagonist on alpha 1 adrenoceptors
Doxazosin is a selective alpha 1 adrenoceptor antagonist.

Which is true of alpha adrenoceptor antagonists

Doxazosin an alpha 1 adrenoceptor antagonist is used to treat hypertension.
Tamulosin, a selective alpha 1a receptor antagonist is used to treat benign prostatic hypertrophy

Which statements describe the clinical use of beta adrenoceptor antagonists---

They are used to treat hypertension
They are used to treat angina pectoris
They are used preoperatively to reduce symptoms and gland vascularity in thyrotoxic patients
They are used to treat cardiac dysrhythmias.

Which are unwanted effects of beta adrenoceptor antagonists

Fall in blood sugar.
Fatigue.
Cause bronchoconstriction in some patients.

A statistical technique used to pool data from several independent but related studies is called

Meta-analysis

Describe Muscarinic receptors

Acetylcholine stimulates muscarinic receptors
Muscarinic receptors cause vascular muscle to relax, indirectly thru production of nitric oxide by the vascular endothelium

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