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76 Cards in this Set

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  • Back
amphetamine derivatives and tyramine cause the release of this?
stored catecholamines
what is the mechanism of action of cocaine and TCA's?
they inhibit the reuptake of catecholamines by nerve terminals and thus increase the synaptic activity of released transmitter
MAO inhibition increases the stores of catecholamines in adrenergic synaptic vesicles what is the effect of this?
MAOI's may potentiate the action of indirectly acting sympathomimetics
epineprhine has affect at what receptors?
all receptor types (a1, a2, B1, B2, B3)
what receptors does pheylephrine act at?
alpha
what receptors does isoproterenol act at?
beta
dopamine can activate these receptors if given as an intermediate dose?
Beta receptors
dopamine can activate these receptors if given in large doses?
alpha receptors
epinephrine, norepinephrine and dopamine are catecholamines that are rapidly metabolized by these enzymes?
COMT and MAO
do MAOs have an effect on phenylisopropylamines (eg amphetamines)?
no amphetamines are resistant to MAO, and most are not catecholamines and so they are also resistant to COMT
what metabolizes tyramine?
MAO
alpha 1 receptor effects are mediated primarily by the trimeric coupling of this protein?
Gq
what happens when Gq is activated?
the alpha moeity of this protein activates phosphoinositide cascade and causes the release of IP3 and DAG from membrane lipids
when IP3 and DAG are released what is the effect?
calcium is subsequently released from stores in smooth muscle cells and enzymes are activated
alpha 2 receptor activation results in this?
inhibition of adenylyl cyclase via the coupling of protein Gi
Beta receptors (B1, B2, B3) stimulate adenylyl cyclase via the coupling of this protein?
Gs
what is the effect of Gs activation?
Gs activation leads to an increase in cAMP concentration in the cell
dopamine D1 receptors activate this in neurons and vascular smooth muscle?
adenylyl cyclase in neurons and vascular smooth muscle
Dopamine D2 receptors are more important in this location?
Brain
do catecholamines enter the CNS effectively?
no
how does the smooth muscle of the pupillary dilator muscle respond to topical pheylephrine and similar alpha agonists?
responds as mydriasis (accomodation is not significantly affected)
what is the effect of alpha agonists on the flow of aqueous humor?
alpha agonists facilitate the outflow of aqueous humor with a subsequent reduciton in intraocular pressure...alpha 2 selective agonists also reduce intraocular pressure apparently by reducing synthesis of aqueous humor
how does the smooth muscle of the bronchi respond to B2 agonists?
relaxation
what is the effect of alpha 2 agonists on the GI tract?
they may decrease salt and water secretion into the intestine
where are alpha 1 receptors located?
most vascular smooth muscle, pupillary dilator muscle, pilomotor smooth muscle
where are alpha 2 receptors?
adrenergic and cholinergic nerve terminals, platelets, some vascular smooth muscle, fat cells, pancreatic beta cells
where are Beta 1 receptors found?
heart and JG cells
where are Beta 2 receptors found?
respiratory, uterine, and vascular smooth muscle, liver, panceratic Beta cells, somatic motor nerve terminals (voluntary muscle)
where are Dopamine D1 receptors found?
renal and other splanchnic blood vessels
where are D2 receptors found?
nerve terminals
what occurs upon stimulation of D1 receptors?
vasodilation (which decreases resistance int eh renal and other splanchnic blood vessels)
what is an example of an alpha 1 agonist?
phenylephrine
what is the effect of phenylephrine?
constriction of skin and splanchnic blood vessels and increase peripheral vascular resistance and venous pressure. - they often invoke compensatory reflex bradycardia
what is an example of an alpha 2 agonist?
clonidine
what is the action of clonidine?
cause vasoconstriction when administered IV or topically (as a nasal spray), but when given orally they accumulate in the CNS and REDUCE sympathetic outflow and blood pressure
give an example of a Beta 2 agonist?
terbutaline
what would be the effect of norepinephrine (both alpha and beta1 effects) on the heart?
may cause reflex increase in VAGAL outflow because they increase blood pressure and evoke the baroreceptor reflex
a pure alpha agonist (phenylephrine) will often have this effect on heart rate?
slows through the baroreceptor reflex
pure beta agonists (eg isoproterenol) almost always has this effect on heart rate?
it increases heart rate
what effect do B1 agonists have on renin secretion?
B1 agonists increase renin secretion
what effect do Beta2 agonists have on the pancrease?
they increase insulin secretion by the pancreas
what is the drug of choice in anaphylactic shock?
epinephrine
epinephrine and this prodrug have been used topically in the treatment of glaucoma?
dipivefrin
what are the newer alpha2 agonists introduced for use in glaucoma?
apraclonidine and brimonidine
what is the recommended prophylaxis for asthma?
a longer acting B2 selective agonist called Salmeterol (not recommended for acute symptoms)
what are the B2 selective agonists that are NOT recommended for prophylaxis but are sage and effective and lifesaving in the treatment of bronchospasm?
short acting B2 agonists = terbutaline, albuterol, and metaproterenol
what type of sympathomimetic would you use in the case of ACUTE heart failure and some types of shock?
Beta 1 agonists = they increase cardiac contractility and reduce (to some degree) afterload by decreasing the impedance to ventricular ejection through a small B2 effect)
this type of sympathomimetic is used with local anesthesia to reduce the loss of anesthetic from the area of injection?
alpha agonists
chronic orthostatic hypOtension due to inadequate sympathetic tone can be treated with these two things?
ephedrine or a newer orally active Alpha 1 agonist, midodrine
what are some examples of Beta 2 agonists that are used to suppress premature labor?
ritodrine and terbutaline
give some other examples of non sympathomimetic agents that can be given to suppress premature labor?
NSAIDS, calcium channel blockers, and magnesium
long acting oral sympathomimetics such as ____ are sometiems used to improve urinary continence in children with enuresis and in the elderly
Ephedrine
what mediates the anti eneurisis action of ephedrine?
alpha receptors in the trigone of the bladder and in men the smooth muscle of the prostate
alpha 1 agonists can have this side effect?
hypertension
beta 1 agonists can have this side effect?
tachycardia and serious arrhythmias
B2 agonists can have this side effect?
skeletal muscle tremor
what are the major toxicities of cocaine?
cardiac arrhythmias or infarction and convulsions.
what two drugs are used for shock and heart failure?
Dopamine and Dobutamine
what drug is used for narcolepsy, obesity and ADD?
Amphetamine, phenmetrazine and others
what drug is used to cause mydriasis, vasoconstriction and decongestions?
Phenylephrine
what drugs are used for asthma?
albuterol, metaproterenol, and terbutaline
what drugs are used to cause nasal decongestion (long action)?
oxymetazoline, and xylometazoline
what drug is used to cause vasoconstriction and is used as a local anesthetic?
cocaine
what drug is used to cause vasoconstriction in hypOtension?
norephinephrine
what drug is used for asthma and AV block?
isproterenol
what drug is used for anaphylaxis, glaucoma, astham and to cause vasoconstriction?
catecholamines, epinephrine
what drug is used for urinary incontinence and to cause vasoconstriction in hypOtension?
ephedrine
which drug is a direct Alpha1, a2, B1 and B2 agonist?
epinephrine
what drugs are an indirect catecholamine releasers?
**Tyramine, also amphetamine and ephedrine
what drugs are indirect catecholamine uptake inhibitors?
**Cocaine, also TCAs
which drug has more alpha 1 action than alpha 2?
phenylephrine (also mehtoxamine, metaraminol and midodrine)
which drug has greater alpha2 than alpha 1 action?
clonidine
which drug has equal B1 and B2 action?
isproterenol (B1 = B2 actions)
which drug has greater B1 than B2 action?
dobutamine
which drug has greater B2 than B1 action?
terbutaline (also albuterol, metaproterenol and ritodrine)
which drug is a dopamine agonist?
dopamine and bromocriptine