Pharmacodynamics Flashcards
Pharmacodynamics is the study of — and —- effects of drugs and it’s — of —-
Biochemical, physiological, mechanism of action
Simplified, pharmacodynamics refers to ——
Effects of a drug on the body
A receptor exists in two in uninterchangeable state. T/F
False. Interchangeable
What are the two states of the receptor
Active and inactive(Ra and Ri)
Binding of a drug to a receptor shifts the equilibrium in one direction alone
False. It’s in either direction depending on where it binds
Intrinsic activity is the capacity to ——-
Induce a functional change in the receptor
Affinity is the strength of irreversible interaction between a drug and its receptor
False. Reversible
Affinity is measured by?
Dissociation constant
A drug that interacts with only a single type of receptor that is expressed on only a limited number of differentiated cells will exhibit———
High specificity
What is an agonist?
It is a drug/substance that binds to a receptor inside a cell or on the surface of a cell and causes the same action as the substance that normally binds to the receptor
Drugs that bind to physiological receptors and mimic regulatory effects of the endogenous signaling compounds are termed?
Agonist
If the drug binds to the same recognition site as the endogenous agonist it is said to be?
A Primary agonist
Allosteric agonists bind to a different region. T/F and it’s referred to as?
True. Allosteric site
What is the binding site for the natural(endogenous) agonist called?
Primary or orthosteric site
Drugs that block or reduce the action of an agonist are termed?
Antagonist
Antagonism most commonly results from competition with an agonist or overlapping site on the receptor. T/F
True
Physical anatagonist binds to the drug and prevents it’s ——— like———
Absorption like charcoal binds to alkaloid and prevents their absorption
Chemical antagonist combines with a substance chemically like——
Chelating agents bind with the metals
A physiological antagonist binds to a different receptor molecule producing an effect ——- to that produced by the drug it ——-
Opposite, Antagonizes
Adrenaline causes ——— by binding to ———
Bronchodilation, B2 receptors
Histamine causes —— through——- receptors
Bronchoconstriction, H1
Agents that are only partly as effective as agonists regardless of concern employed are called?
Partial agonist
A ligand that binds to a receptor and produces the opposite pharmacological effect that would be produced by an agonist is called?
Inverse agonist
Inverse agonist produce effects opposite that of the agonist. T/F
True
What is efficacy?
The maximal effect an agonist can produce
How is efficacy measured?
Graded Dose-response curve
What is potency?
The amount of drug needed to produce a given effect!
How is potency determined?
The affinity of the receptor for the drug
The measure of the potency of a substance in inhibiting a specific biological or biochemical function is known as?
Half maximal inhibitory concentration
The dose required for an individual to experience 50% of the maximum effect
EC50
What is ED50
The dose for 50% of the population to obtain the therapeutic effect
Repeated administration of a drug results in?
Diminished effect “Tolerance”
A type of tolerance which occurs very rapidly is called?
Tachyphylaxis
Decreased response to agonist after it’s repeated injections in small doses is called?
Desensitization
Desensitization can occur due to
Internalization of receptors(endocytosis)
Loss of receptors (due to lack of synthesis or increased destruction)
Exhaustion of mediators(depletion of catecholamine)
DRC of a competitive antagonist has a parallel right shift. T/F
True
Is non-competitive antagonist surmountable?
No. It isn’t
Competitive anatagonists inactivates a certain number of receptors. T/F
False! It’s the agonist molecules. This is for uncompetitive
Intensity of responds depends on only antagonist in competitive antagonist interactions
False! It depends on both agonist and antagonist
Examples of competitive antagonist interaction
Ach———Atropine
Morphine——-Naloxone
Examples of non competitive
Diazepam——-Bicuculline
When the action of one drug is facilitated or increased by another it is said to be?
Synergistic!
In synergistic pair, only one drug can have action in a direction. T/F
False! Both of them can have
In synergistic pair one may be inactive but still enhance the action of the other. T/F
True
Physiological receptors include?
GPCR
Ion channels
Transmembrane enzymes
Transmembrane non-enzymes
Nuclear receptors
Intercellular enzymes
What are the two major functions of physiological receptors?
Ligand binding
Message propagation(signaling)
Functional domains within the receptor
Ligand binding
Effector
The regulatory actions of a receptor may be exerted directly on its ——, on —— or may be conveyed by intermediary cellular signaling molecules called ——
Cellular target, effector proteins, transducers
What are the functional families of ion channels?
Ligand gated and voltage gated
Physiological ligands of ligand-gated ion channels?
Ach, GABA, 5-HT
Physiological ligands of voltage ion channels
None because they are activated by membrane depolarization
Effectors and transducers of ligand gated and voltage gated channels?
Na, Ca, K, Cl for ligand gated and same for voltage gated with exception of chloride
Examples of drugs that act on ligand gated channels?
Nicotine
Gabapentin
Examples of drugs that act on voltage gated channels
Lidocaine
Verapamil
What kind of receptors are the fastest
Receptors with intrinsic ion channels
Examples of receptors with intrinsic ion channels
Ligand gated ion channels
Classify these voltage sensitive calcium channels according in relation to these properties. L, T, N, PQR
1)Activation threshold
2)inactivation rate
3)location
4)Function
5)Blockers
Blockers
L-Verapamil and dihydropyridine group of CCBs and Cd2+
T-Ethosuxinide
Flunarizine
Ni+
N-Cd+
Gabapentin
PQR
Toxin from funnel web spider
Q channels have properties similar to P channels. T/F
True
The neuronal pharmacology of CNS is modulated by what channels?
N, P, Q, R
What channel has weak effects on CNS functions?
L channel
Functional families of GCPR includes?
Beta adrenergic receptors
Muscarinic receptors
Eicosanoid receptors
What are the physiological ligands of Adrenergic receptors, muscarinic and eicosanoid receptors?
A-NE, Epi, DA
M-Ach
E-prostaglandins
Leukotrienes
Thromboxanes
What are the effectors and transducers and examples of drugs for Adrenergic, muscarinic and eicosanoid receptors?
Adrenergic-Gs, AC… Eg is Dobutamine
Muscarinic-Gi, Gq, AC, ion channels, PLC. Eg Atropine
Eicosanoid-Gi, Gq, Gs.. Eg mistroprostol, montelukast
GCPRs is a family of —— GTP binding regulatory proteins called ——
Heterotrimeric, G-proteins
The G-protein heterotrimer is composed of a —— and an —-
Guanine nucleotide-binding alpha subunit , associated dimer beta and gamma subunits
G-protein regulated effectors include enzymes such as?
Phospholipase C
Adenylyl Cyclase
cyclic GMP phosphodiesterase(PDE6)
Membrane ion channels selective for Ca and K
GCPRs span the PM as a bundle of —- alpha helices
7
GCPR is a cystolic binding site for —— and extracellular binding site for ——
G-proteins and ligands
Function of Gi subunits?
Inhibit certain isoforms of adenylyl cyclase
Gs alpha subunit function
Stimulate/activate adenylyl cyclase
Gq subunit function
Activates all forms of phospholipase C
What GPCR subunit is coupled to guanine nucleotide exchange factors(GEFs) such as p115RhoGEF for the small GTP-binding proteins Rho and Rac
G12/13
Phosphorylation can cause?
SM relaxation
Heart contraction
Glycogenolysis
Lipolysis
