Pharmacology Flashcards
what causes a parallel right shift in the response curve with no depression?
reversible competitive antagomism
what do nuclear receptors do?
regulate gene transcription
which drugs can act as agonists at the acetylcholine receptors (nAchRs) ?
acetylcholine
nicotine
varenicline
which kind of receptor is involved in signal amplification?
G protein coupled receptor
what is occupying alpha binding site when there is no signalling?
GDP
what hydrolyses GTP to GDP + Pi when turning signal off?
alpha subunit
what does alpha 1 do?
blood vessel vasoconstriction
what does alpha 2 do?
presynaptic inhibition of noradrenaline in CNS
GI tract relaxation
Decrease in persistalsis
what does beta 3 do?
thermogenesis in skeletal muscle
lipolysis
what does beta 1 do?
inc. heart rate & cardiac muscle contraction
tachycardic response
what does beta 2 do?
bronchodilation
inc. heart rate & cardiac muscle contraction (lesser extent than Beta 1)
what can activate cyclic AMP (cAMP) second messenger pathway?
G-protein coupled receptors
state the selectivity & extent of agonist of nicotine, varenicline & acetylcholine
nicotine: full agonist, selective
varenicline: partial agonist, selective
acetylcholine: full agonist, non-selective
greater pKi means greater or lesser affinity for receptor?
greater
lower KA means greater or lesser affinity for receptor?
greater
what does the Hill-Langmuir equation model?
relationship between ligand concentration and receptor occupancy
what is EC50?
concentration of agonist that elicits half maximal effect
what does non-competitive agonism do to the sigmoidal curve?
depresses the slope & maximum response curve
no right shift
what is pKa?
pH at which 50% of the drug is ionised and 50% is unionised
what is bioavailability (F)?
how available to exert effect, the amount of drug that eventually reaches systemic circulation
what is the bioavailability calculation?
quantity of drug reaching systemic circulation (AUC) / Quantity of drug administered (dose)
what can clearance be broken down into?
renal (CLR)
hepatic (CLH)
other elimination routes (CLO)
total clearance (CLT)
how do you calculate clearance? (CL)
rate of drug elimination/ [drug] plasma
what is first order kinetics?
initially, the rate of drug elimination increases as drug plasma increases (follows Michaelis-Menten kinetics)
