Concepts & terms Flashcards
activates the receptor as a direct result of binding to it
agonist
produces a lower response at full receptor occupancy; concentration curve resembles that of the full agonist with some antagonist bound to the receptor sites
partial agonist
binds to the receptor but doesn’t activate generation of a signal; primary action is to interfere with the action of the agonist
antagonist
competes with the agonist for the receptor site
competitive antagonist
duration of action of irreversible antagonist
largely determined by the rate of turnover of the receptors and not its rate of elimination
the concentration of drug that produces 50% of max effect
EC50
the transduction process that links drug occupancy of receptors and pharm response
coupling
helps elicit a maximal biological response at a concentration of agonist that does not result in occupancy of the full complement of available receptors
spare receptors
can cross the plasma membrane and act on an intracellular receptor
corticosteroids mineralocorticoids sex steroids vitamin D thyroid hormone
endogenous ligands that regulate the flow of ions through the plasma membrane
acetylcholine
serotonin
GABA
glutamate
G protein-coupled receptor NTs/ligands
adrenergic amines serotonin muscarinic ACh peptide hormones odorants
degrades cAMP and IP3, respectively
caffeine (cAMP) lithium ion (IP3)
the dose of drug required to produce 50% of maximal effect of the drug; refers to the potency
ED50 = median effective dose
dose required to produce a toxic effect in 50% of animals
TD50 = median toxic dose
toxic dose required to produce death in 50% of animals
LD50 = lethal toxic dose
the ratio of the TD50 to the LD50
therapeutic index
what the body does to a drug: absorption distribution metabolism excretion
pharmacokinetics
what the drug does to the body:
side effects
toxicity
withdrawal reactions
pharmacodynamics
mimic actions of epinephrine or NE
sympathomimetics
directly interact with and activate adrenoreceptors
direct agonists
actions depend on the abilities to enhance the actions of endogenous catecholamines
indirect agonists
intracellular signaling pathway that promotes release of sequestered Ca2+ increasing intracellular calcium and activating calcium-dependent kinases
IP3
activates protein kinase C
DAG
enzyme that increases cAMP
beta receptors and D1 receptors activate this enzyme
alpha 2 and D2 receptors inhibit it
adenylyl cyclase
primary location of beta 1 receptors
heart
activation increases contractility and direct activation of the SA node
mediate urinary continence
alpha receptors in bladder base, urethral sphincter and prostate
Note: alpha1 receptor activation causes constriction
receptor that plays a role in normal ejaculation
alpha
agonist at both alpha and beta receptors
- potent vasoconstrictor & cardiac stimulant
- increases HR and contractility
epinephrine
agonist of both alpha and beta1 receptors
- increases peripheral vascular resistance in both systolic and diastolic bp
- compensatory baroreflex of heart overcomes the chronotropic effects, but positive inotropic effects are maintained
norepinephrine
immediate precursor to NE
dopamine
action of indirect-acting sympathomimetics
they are “amphetamine-like” because they displaced stores catecholamine NT and interfere with NET
