F. Pharmacology & ADME Flashcards

1
Q

What are the molecular targets on cells which drugs usually interact with? and give examples

A

Proteins:
* Enzymes
* Transporters/pump proteins
* Ion Channels
* Receptors

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2
Q

What is a receptor?

A

Proteins which respond to a endogenous (native) messenger by initiating a a signal

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3
Q

What are the common characteristics of receptors?

A
  • Selective binding site for native hormones/ transmitter
  • Act as molecular switches-inactive and actives states
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4
Q

What is the ANS?

A

A component of the perhipheral nervous system that regulates unconcious physiological control of organ systems.

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5
Q

What are the divisions of the nervous system?

A
  • CNS
  • PNS
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6
Q

describe the features each divison of the nervous system

what connects the PNS to the CNS

A

CNS
- Brain + spinal cord

PNS
-sensory nerves (afferent fibres)
-motor nerves (somatic efferent fibres)
-autonomic nerves ( nerves involved in unconcious physiological control of organ systems)

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7
Q

What are the divisions of the ANS

A
  • Sympathetic NS
    (fight or flight)
  • Parasympathetic NS
    (rest and digest)
  • Enteric NS
    (GI tract)
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8
Q

what type of sympathetic receptors are found in the heart?

A

beta-1 AR

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9
Q

What type of sympathetic receptors are in the lungs and skeletal muscle?

A

beta-2 AR

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10
Q

What type of sympathetic receptors are in skin, GI tract and brain?

A

alpha-1 AR

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11
Q

What type of sympathetic NS receptors are in the skin for sweat gland secretion?

A

MR -Ach

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12
Q

Define an agonist

A

a drug or natural substance tht binds to and activates a receptor

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13
Q

define an antagonist

A

a drug or natural molecule that binds to a receptor but doen’t activate the receptor

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14
Q

agonist have both …. and …. for a receptor

A

affinity and efficacy for a receptor

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15
Q

antagonists have only …. and not … for a receptor

A

affinity but not efficacy

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16
Q

What is an on-site side effect?

A

a drug bind to the same type of receptor but at a different site

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17
Q

what is an off-site side effect?

A
  • binds to a different type of receptor and somewhere else from the target
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18
Q

which type of g-protein are alpha-1 ARs coupled to

A

Gq

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19
Q

What type of G-protein are alpha-2 ARs coupled to

A

Gi

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20
Q

what type of of g-proteins are beta AR coupled to

A

Gs

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21
Q

what effects does each type of Gprotein cause?

A

Gs-increases cAMP and PKA, relaxation of smooth muscle

Gi-decreases cAMP, PKA- inhibition of sympathetic NS acts as a regulator

Gq- increases calcium levels, contration of smooth muscle

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22
Q

Describe the signal transduction pathway of Gs PCRs

A

NA binds, Gs binds to adenylyl cyclase, Atp to cAMP, inactive PKA to active PKA, target protein is phosphorylated

23
Q

Describe signal transduction in Gq PCRs

A

NA binds, Gq moves to PL C, PIP2 binds to PL C, hydrolyses to products are IP3 and DAG , IP3 bind to receptor channels to open ca 2+ stores

DAG does it’s own stuff

23
Q

What is affinity

A

The ability of a drug to bind to it’s receptor

24
Q

What is efficacy?

A

The ability of a drug, once bound, to activate the receptor via onformational change

25
Q

What is the law of mass action?

A

rates of binding/dissociation are proportional to concentration of drug and receptors

26
Q

what is Kd + equation

A

equilibrium dissociation constant- the concentration where of frug needed to occupy 50% of receptor binding sites at euilibrium = conc. dxr/ conc dr

27
Q

what is Rmax

A

Max effect of the drug determined by conc of drug

28
Q

what is Ec50

A
  • the conc that produces the half of max effect of the drug
29
Q

what is a full agonist?

A

produces the same max effect, as good as counterpart’s response

30
Q

what is a partial agonist

A

an agonist with lower efficacy-ability to activate

31
Q

anatagonists can be …. and ….

A

competitive (receptor binding is competed by both agonist and antag.) and reversible (bonding non-covalently and dissocitation)

32
Q

What is surmountable antagonism?

A

In the prescence of the antagonist the maximmal agonist response is the same Rmax doesn’t change

33
Q

what is non-surmountable antagonism

A

in the prescence of an antagonist the maximal agonist response reduces, Rmax reduces

due to non-competitive/irreversible antagonists

34
Q

what is an irreversible antagonist?

A

forms covalent bond and doesn’t dissociate, blocking the binding site for the agonist and reduces the Rmax

35
Q

The Rmax depends on two things

A
  • Affinity and efficacy of the drug
  • properties of the response aka receptor reserve e.g. amplification even when not even 50% of receptors are occupied
36
Q

What determines drug distribution?

A
  • affinity to binding sites in plasma proteins
  • structure of cppillary endothelium
  • accumlating in cetain tissue (tissue depots)-which may be the target or not
37
Q

what are the phases of metabolism?

A
  • phase 1: redox reactions
  • phase 2: conjugation

increased hydrophilicity, reactivity,size less likelyto bind selectively

easier to remove from body

38
Q

Where does excretion mainly take place?

A
  • Kidney
39
Q

Stages of excretion in the kidney where do they occur

A
  1. Passive filtration-glomerelus
  2. Active secretion-proximal tubule
  3. Reabsorption-distal tubule
40
Q

Parameters of ADME

A
  • Absorption: Bioavailability (F), Cmax, Tmax
  • Distribution: Volume distribution (Vd)
  • Elimination: Half life( t1/2), clearance (CL)
41
Q

Explain bioavailablility, Cmax and Tmax

A
  • Bioavailability=the fraction of dose got into circulation
  • Cmax=max conc in circulation, and time taken for drug to reach circulation
42
Q

What is the therapeutic window?

A

the plasma concentration range, where there is a min. conc for therapeutic effct to occur and a max where beyound this concentration there’s an onset of side effects

43
Q

What is first pass metabolism?

A

drug passes through the hepatic portal system before in enters sytemic circulation, some of it is metabolised here so drug conc decreases

44
Q

3 different types of capillaries

A
  • continuous-inetrcellular clefts
  • fenestrated-fenetrations/pores, intercellular clefts
  • dicontinuous- very large intercellular space, very leaky, basement membrane incomplete (liver and glomerulus)
45
Q

Which enzymes are involved with metabolism in liver?

A

CYP450-redox
UGT-conjugation

46
Q

Ciliary muscles and pupillary sphinter muscles are part of which branch of the ANS

A

Parasymp

47
Q

Pupillary dilator muscles are part of which branch of ANS

A

Symp.

48
Q

receptor super families

A
  • GCPRs
  • Nuclear receptors
  • Ligand-gated ion channels
  • Catalytic receptors
49
Q

What two main ways drug is absorbed in gut/small intestine?

A
  • passive diffusion
  • Active transport
50
Q

There are many different G-proteins. They are heterotrimetric which means what?

A

Composed of 3 subunits: alpha, beta and gamma

51
Q

What is the alpha subunit of a g-protein bound to and how does this change when a signal binds to the GPCR ?

A
  • A GDP molecule
  • when the change happens GDP is swapped for GTP
  • trimeric form breaks and alpha subunit of g protein seperates and moves towards the adenylyl cyclase.
52
Q

Where is adrenaline produced?

A

Adrenal medulla gland which sits above the kidney

53
Q
A