Pharmacodynamics Long Slide Flashcards
Drugs interfere with the flow of ions through channels that are specific for these ions. What’s are these ion channels?
Na
K
Ca
Cl
What are the substances that block sodium channels?
What does the block prevent?
What are they used in?
Quinidine
Procainamide
Depolarization leading to nerve conduction block
Cardiac arrhythmias and as local anaesthetics
What drugs block the voltage gated calcium channels?
What are they used in?
Nifedipine
Verapamil
Diltiazem
Arrhythmias and hypertension
Blockade of Potassium channels leads to?
Prolonged refractory period
Potassium channel drugs include?
Which of them is used in arrhythmias?
Sulfonylurea
Amiodarone
Amiodarone
In chloride channels; upon activation, the — receptor selectively conducts Cl- through its pore resulting in — of the neuron which causes — effect on neurotransmission by — the chance of a successful AP occurring e.g —
GABA A
Hyperpolarization
Inhibitory
diminishing
Benzodiazepine
Transport of ions across cell membranes generally requires?
Carrier proteins
Inhibition of choline carrier is by?
Hemicholinium
Inhibition of noradrenaline vesicular uptake is by?
Reserpine
Inhibition of neuronal reuptake of Noradrenaline is by?
Desipramine
Inhibition of neuronal reuptake of serotonin is by?
Fluoxetine
Inhibition of weak acids carrier by drugs— which prevent uric acid tubular —— thus enhancing its ——
Probenecid
Reabsorption
Excretion
Drug receptors are regulatory ——
Macromolecular proteins
What are target sites for most drugs located on the cell membrane but could also be located intracellularly
Receptors
What is the specific chemical constituent of the cell with which drug interacts to produce its pharmacological effects?
Receptors
Receptor concept was attributed to the work of who?
Langley and Erlich… Late 1800-early 1900
What are ligands?
Ligands are substances that interact at the receptor binding site
Ligands are only exogenous
F….Could be exogenous or endogenous
Receptors are —— components of a cell with which a drug interacts to produce a response
Macromolecular
Drug-receptor interaction is lickened to what model?
Lock and key model
What are the characteristics of a receptor?
Sensitivity
Specificity
Selectivity
Saturation
What are the molecules serving as receptors?
Membrane proteins(lipoproteins, glycoproteins)
Enzymes
Nucleic acid
Complex polysaccharide
An agent which activates a receptor to produce an effect similar to that of the physiological signal molecule?
Agonist
Examples of agonists
Adrenaline, noradrenaline, acetylcholine
An agent which prevents the action of an agonist on a receptor but has no effect on its own is called?
Antagonist
What is a partial agonist?
An agent which activates a receptor to produce submaximal effects but antagonizes the effect of a full agonist
Examples of antagonist?
Atropine
Scopolamine
Phenoxybenzamine
An agent which activates a receptor to produce an effect in the opposite direction to that of the agonist is?
Inverse agonist
Endogenous substances
Adrenaline
Noradrenaline
Glutamate
Aspartate
GABA
Ach
Examples of inverse agonist?
Beta carbolines
The tenacity by which ligands bind to its receptor is called?
Affinity
Some drugs possess EFFICACY but not AFFINITY
False. It’s the opposite
The capacity to induce functional change in the receptor in a way that produces effect is known as?
Intrinsic activity
In terms of Affinity and Intrisic activity classify Agonist, antagonist, PA, IA
Agonist: 1
Antagonist: 0
Partial agonist:IA between 0 and 1
Inverse Agonist:IA between 0 and -1
What are the Drug receptor binding forces?
Covalent bond
Ionic bond
Hydrogen bond
Van-der-waals
What type of force do most drugs employ?
Ionic bond
What force has a bond that is strong and not reversible under biological conditions
Examples?
Covalent bond
Organophosphate and anticholinesterases
Specific conformational perturbation(by agonist) leads to no biological response. T/F
False. Leads to one
Non-specific conformational perturbation(antagonist) leads to no biological response
True
The idea that a response emanates from a receptor only when it is occupied by an appropriate ligand and the response is proportional to the fraction of occupied receptors is what theory?
Occupancy theory
The idea that a response emanates from a receptor in proportion to the kinetic state of onset and offset of a drug binding to the receptor is known as what theory?
Rate theory
In what theory is response proportional to the fraction of occupied receptor and intrinsic activity
Stephensons theory
In what theory is response a function of affinity and can maximum response be produced without 100% receptor occupation?
Ariens theory
In what theory is it said that the binding site is not necessarily complementary with ligand conformation? Nullifying the obsolete key and lock concept
Induced fit theory
What theory depends on drug-receptor complex dissociation?
Rate theory
What are the two essential functions of receptors?
Recognition of specific ligand
Transduction of signal into response
What are the two domains on a receptor ?
Ligand binding domain
Effectors domain
What receptor domain undergoes functional conformational change?
Effectors domain
What is not a hypothesis anymore?
Nature of receptors
What happens to cell surface receptors?
They remain floated in cell membrane lipids
Functions of a receptor are determined by?
Interaction between hydrophilic and lipophilic domains of the peptide chain within the drug molecule
About receptors;
Non-polar hydrophobic portion of amino acid remain ——in —— while —— hydrophilic remain on cell surface
Buried
Membrane
Polar
What is the classical and oldest approach of receptor classification, based on
potencies of selective agonist and antagonists – Muscarinic, nicotinic, alpha
and beta adrenergic etc.
Pharmacological criteria
What criteria for reception classification has to do with basis for designation of subtype?
Give examples
Tissue distribution
Cardiac beta adrenergic receptor as beta1 and bronchial as beta 2
