Drugs
What drug is used as an antagonist for B1, B2, and alpha receptors?
Labetalol
What ligand acts on muscarinic receptors?
Acetylcholine.
Recall the equation for calculating steady state.
Css= F (dose)/T (CL)
Name 3 symptoms of cholinergic excess.
Diarrhea
Urination
Muscle weakness
Bronchorrhea
Bradycardia
Emesis
Lacrimation
Sweating/salivation
Name the two receptors that are found BOTH presynaptically and postsynaptically.
B2: presynaptic will take up Epi and release Norepi
Postsynaptic will relax smooth muscle, start glycogenolysis, increase heart rate
M2: Presynaptic is acetylcholine autoreceptor
Postsynaptic decreases heart rate
A researcher studies the dose–response curve of a full agonist acting at β₂-adrenergic receptors. When a noncompetitive reversible antagonist is added to the experiment, the agonist’s dose–response curve shifts.
Describe how the addition of this noncompetitive reversible antagonist affects the agonist’s EC₅₀ and maximal efficacy (Emax).
Noncompetitive agonist will DECREASE efficacy and keep EC50 the same.
Binds to a site different from the agonist's binding site.
Justin tries to do a one-armed pushup in the library and fails. As a result, norepinephrine is released from postsynaptic terminals. This causes the release of acetylcholine to come to a halt, and his heart rate begins to increase. What KIND of receptor is at play, and why is acetylcholine no longer released?
Heteroreceptor; norepinephrine binds to the acetylcholine heteroreceptor and causes termination of acetylcholine release.
Isaac had too much chick-fil-a and is prescribed clopidogrel after receiving a coronary stent. Despite excellent medication adherence, he develops stent thrombosis. Genetic testing reveals that he has a mutation in the gene for CYP2C19. How is this possible?
Clopidogrel is a prodrug.
A researcher studies cardiac muscle contractility. When an irreversible (noncompetitive) β-receptor antagonist is added, the maximal contractile response remains unchanged until more than 90% of the receptors are blocked.
Explain how the tissue is able to maintain its maximal response despite most receptors being inactivated. What concept is illustrated?
Spare receptors