Trachte Week 3 Flashcards
Name three sympathomimetics that induce release of norepinephrine, but NOT dopamine B hydroxylase?
tyramine, amphetamine, ephedrine
How do indirectly acting sympathomimetics act to induce release of norepi?
they reverse the direction of the axoplasmic catecholamine transporter
What drugs make the action of tyramine, amphetamine and ephedrine inactive? how?
imipramine, cocaine via inhibition of the axoplasmic pump
What med inhibits the granular pump accumulating catecholamines in vesicles (results in depletion of catecholamines)?
Reserpine (Serpasil)
Name the med that induces release from vesicle, probably via displacement, slow acting (nor epi gets degraded by MAO), depletes norepi stores, reduces responses to sympathetic stimulation, inactive in the presence of inhibitors of the axoplasmic transporter or MAOIs
Guanethidine
What is present in the liver and is needed for inactivating circulating catecholes?
COMT
What blocks the COMT and is used as adjunct tx in Parkinsons?
Tolcapone (Tasmar)
What is the function of MAO? What blocks it’s action?
oxidizes catecholamines, perlindole in the intestine and brain, seligeline and PARGYLINE in various organs
What is the purpose of MAOIs?
potentiate the action of catecholamines
What do you have to avoid when taking an MAOI? why?
Foods containing tyramine, because they also release catecholamines and are normally degraded by MAO in the intestine
What is the predominant end product of norepi?
vanilylmandelic acid in urine
Name the receptor: adrenergic cardiac effects, renin release, located in heart, JG apparatus and adipose, acts to increase cAMPT via Galphas
Beta1 (isoproterenol>epinephrine=norepinephrine)
Name the receptor: mediates smooth muscle contraction (primary CV location is blood vessels), activates phospholipase C (Galphaq dependent process) to increase intracellular calcium via inositol triphosphates
Alpha1 (epinephrine > norepi»_space;isoproterenol
Name the receptor: inhibition of neural norepinephrine release, prejunctional nerve terminal, platelets, gut, medulla oblongata, acts to decrease cAMP or activate cAMP or activate Na/H antiporter, Galpha dependent process
Alpha2 (epi>norepi»isoproterenol)
Name the receptor: relaxation of smooth muscle and metabolic (glycogenolytic) effects, primary site in CV system is blood vessels (smooth muscle in general), acts to increase cAMP via Galphas
Beta2 (isoproterenol > epi»_space; norepi)
What is the action of Dobutamine?
selective B1 agonist, positive ionotrope
Define Ionotrope
increases cardiac contractility (ie Ca to increase Ca from SR)