PHAR 340 Lecture Notes - Lecture 3: Tachyphylaxis, Coordination Complex, Digoxin
23 Dec 2018
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Drugs have opp effect but via diff receptor sys. H + rh decreases bp e +re increases bp. Not r mediated, 1 drug binds to 2nd drug to inact it. Ex. heavy metals + chelating agent metal complex. Max response w/o full r occupancy, can be seen w low conc of irrev antagonist, as u add more irrev antagonists dose curve shifts r. Sparseness can be temporal effect of r act outlast agonist-r interaction ex. R dn need to be occupied for response to occur. Aka upregulation of agonists freq following reduction in r stim, can have increased # of rs ex. after long-term treat w antagonist. Due to continued stim w agonists, decreased rs or signaling, effect of drug diminishes. Tachyphylaxis rapid desens assoc w depletion of cellular signaling mediator (ex. camp) Each indiv response at diff time to drug, quantal response. Ed50 median effective dose- dose that elicits response in 50% of indiv.
