Intro to Pharmacology Flashcards

1
Q

ligand definition

A

a chemical or compound that binds to a receptor

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2
Q

agonist definition

A

a compound that binds to an activated a receptor

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3
Q

antagonist definition

A

a compound that reduces the effect of an agonist at a receptor

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4
Q

partial agonist

A

a low efficiency agonist that is unable to elicit the maximal response from a receptor, irrespective of the concentration applied

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5
Q

affinity definition

A

a measure of the equilibrium constant of the reversible reaction between a drug (agonist or antagonist) and a receptor

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6
Q

efficacy definition

A

a measure of the magnitude of the (cellular) response produced when an agonist binds to receptor

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7
Q

potency definition

A

a measure of the concentration f a drug at which it produces an effect of a given magnitude

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8
Q

specificity definition

A

a measure of the number of receptor sites that a given drug may bind to or the range of effects it may produce

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9
Q

selectivity definition

A

the degree to which a drug binds to a given receptor site relative to other sites (related to affinity)

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10
Q

what is a drug

A

a chemical substance intentionally administered that alters body function, which is used for the prevention of treatment of a disease

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11
Q

what is the difference between a drug and a medicine

A

a medicine contains other substances
- stabilisers/ solvents
- more convenient

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12
Q

what do drugs target (4)

A

receptors (most targeted)
enzymes
carrier molecules (transporters)
ion channels

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13
Q

what does it mean if both agonist and antagonist can act on a receptor

A

there must be chemical similarities between them
there must also be chemical differences (why one activates and one blocks)

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14
Q

affinity lock and key analogy

A

affinity is how well the key fits the locke

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15
Q

efficacy lock and key analogy

A

efficacy is how well the key can turn the lock
efficacy is graded

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16
Q

receptor occupancy

A

hyperbolic relationship
- as the receptor needs to be occupied to be activated in order to elicit a response, the dose-response curve of an agonist is also hyperbolic

17
Q

dose response curves

A

allows estimation of the maximal effect/ response (Emax) a drug can produce
- estimate the conc. of a drug needed to produce a half maximal response (EC50)
- EC50 used to compare efficacy between drugs

18
Q

measuring EC50 on hyperbolic curves

A

is harder
- common practice to plot the same data but on a semi-log scale

19
Q

high potency =

A

high affinity for the receptors

20
Q

do antagonists posses affinity and/or efficacy

A

only affinity
no response, no efficacy

21
Q

mechanisms of antagonist

A

by binding to the same site as the agonist and competing with it (competitive)
binding to a different site to the agonist, which causes a change in the receptor to prevent or restrict agonist binding (non-competitive)

22
Q

competitive antagonists

A

binds to the endogenous ligand and competes for binding
concentration and affinity determines the ‘winner’ of the competition
no response/ response
effect of a competitive antagonist can be overcome by increasing agonist concentration

23
Q

non-competitive antagonists

A

binds to a different site -> conformational change restricts agonist binding
cannot be overcome by increasing agonist concentration
partial response