Pharm 212 Sequential Exam 1 - Drug Receptors

what is a molecular complex that binds drugs/endogenous agents resulting in a pharmacological/physiological resonse

receptor

what is a drug that elicits a pharmacological response when it binds to a receptor

agonist

what is an agent that reduced the effectiveness of a corresponding agonist

an antagonist

what is the ability to bind to a receptor

affinity

what is the ability to produce a pharmacological action after binding

intrinsic activity

what is the x-y axis scale for drug-receptor interaction graphs

Log [A] V % maximal response

which drug is the more potent drug

Drug X — it requires much less concentration to achieve the same effect

which drug has a higher activity

Drug X — it reaches a higher efficacy than drug Y

which interactions have receptor affinity and intrinsic activity

Agonists

which interactions have receptor affinity but have reduced intrinsic activity

partial agonists

which interactions have receptor affinity but lack intrinsic activity

pure antagonists

which interactions bind to the receptors in an inactive state, which might also show antagonism

inverse agonists

understand the different aspects of this graph

—

what type of mechanism does this graph indicate

competitive

what kind of mechanism does this graph indicate

pseudo-irreversible

what kind of mechanism does this graph indicate

allosteric

what is the selectivity of agonist/antagonist binding to a specific class of receptors

receptor specificity

how can we quantitatively relate the toxic and therapeutic effects of a drug through dose-response

therapeutic index

how do we calculate therapeutic index

what does this exemplify?

therapeutic index

coupling or signal transduction

what is it called when ligand binding must be transduced into the cell to produce a physiological response

spare receptors

what are unequal proportions or rations between receptors and effectors, either within time or space

what do spare receptors do

serves to make drugs more or less effective by increasing or decreasing sensitivity

what is the clinical definition of spatially spare

when 100% response is elicited by less than full receptor occupancy = spare in numbers

what causes receptor desensitization

due to intracellular signaling feedback inhibiting the receptor machinery

how long does receptor desensitization last

usually a few minutes up to one hour

receptor down-regulation

what results from agonist-induced decreases in receptor number

degradation in lysosomes and recycling to the plasma membrane restoring function

what is are the receptor effects of drug tolerance

super sensitivity

what is the other regulatory response

tachyphylaxis

what is a reduction in response after acute readministration of a drug

hypersensitivity

what is an allergic reaction to an antigen

idiosyncratic reaction

what is an abnormal reaction to a drug that may result from a genetic predisposition

synergy

what is it when two or more drugs result in a response that is greater than the sum of their individual intrinsic activities

what does the graphic describe

different transmembrane signaling mechanisms

lipid crossing

requires a lag period if 30 minutes to several hours, effects are long lived, several hours to days, even after the ligand has dropped to zero

ligand regulated enzymes

the binding of the ligand to receptor does 3 things:

1. exposes tyrosine sites

2. activates tyr-kinases

3. activates kinases to alter cell physiology

what are the consequences of ligand regulated enzymes

cooperative binding and long-lasting effect

Activation of JAK- STAT

binding of the ligand to the dimer causes:

1. dimer formation

2. activates mobile kinase

3. JAK phosphorylation of receptor protein and STAT transcription factor

4. STAT can migrate to the nucleus and promote gene transcription

ligand-gated ion channels

binding of the ligand causes:

1. creates conformational shift in subunit structure

2. opens aqueous channel allowing sodium ions to enter

features an on/off switch