drug receptor interactions

Question 1

what is a drug

Answer 1

substance that interacts with a biological system to produce a physiological effect

Question 2

target sites of drugs and commonality

Answer 2

receptors, ion channels, transport systems and enzymes, which are all proteins

Question 3

explain 1st drug target site: define, what activated by, how many types

Answer 3

receptors are proteins within cell membranes apart from steroid receptors activated by hormone or NT 4 types

Question 4

agonist vs antagonist and examples

Answer 4

agonists are ligands that simulate receptors, antagonists block them acetylcholine+nicotine vs atropine

Question 5

explain 2nd drug site, types and examples

Answer 5

ion channels are either voltage sensitiv or receptor linked eg nAChR calcium channel blockers

Question 6

explain 3rd drug site with examples

Answer 6

transport systems is transport against conc gradient eg glucose cotransports, NaK pump, NT’s TCA’s (anti-depressants) and cardiac glycosides

Question 7

explain 4th drug site with examples

Answer 7

enzymes can be targeted by enzyme inhibitors (anticholinesterases), false substrates (methyldopa) or produgs (precursors like chloral hydrate, which becomes trichloroethanol)

Question 8

explain non-specific drug binding

Answer 8

drugs that dont interact with proteins, like antacids to reduce stomach pH, and osmotic purgatives to prevent constipation by drawing water into gut

Question 9

explain plasma protein binding

Answer 9

drug bound to it is inactive

Question 10

what affects potency of a drug (with RECEPTOR)

Answer 10

affinity (binding property of drug to receptor) and efficacy- what drug does to receptor: often undergoes conformational change

Question 11

types of agonists

Answer 11

full agonist and partial: partial has some antagonist activity

Question 12

explain structure activity relationship

Answer 12

drugs are selective- small changes in structure completely change activity: agonists can become antagonists

Question 13

explain dose response curve (full vs partial) DIAGRAM

Answer 13

measure tissue response by agonist concentration full agonist structure can be changes to form partial agonist- curve can determine whether partial agonist forms

Question 14

explain log dose response (DIAGRAM)

Answer 14

shape is a sigmoid curve- full agonist with lower affinity has same max response, but higher dosage needed

Question 15

explain antagonists- types with examples (DIAGRAM)

Answer 15

drug with have affinity but NO efficacy competitive have same site as agonist, but are surmountable, so shifts curve to right eg atropine non-competitive bind to different site and are insurmountable eg hexamethonium