Lecture 11 - Signalling Molecule And Drug Targets Flashcards

1
Q

What is a ligand?

A

A signalling molecule that binds to a target/receptor

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2
Q

Are nearly all of the Antagonists endogenous or exogenous?

A

Exogenous

There are very few endogenous antagonists

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3
Q

What is the pneumonic for the target of signalling molecules/drugs?

A

RITE

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4
Q

What does the pneumonic for drug targets RITE stand for?

A

Receptors
Ion channels (Voltage gated)
Transporters
Enzymes

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5
Q

Receptors can be further categorised, what is the pneumonic for these categories?

A

K(L)ING

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6
Q

What does the pneumonic K(L)ING for the categories of receptors stand for?

A

Kinase linked receptors
Ion channels (Ligand gated)
Nuclear/intracellular
G Protein Coupled Receptor

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7
Q

How can the activity of an ion channel be changed?

A

Allosteric phosphorylation

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8
Q

What Voltage gated ion channels are normally targeted by drugs?

A

VGSCs (Voltage gated sodium channels)
VGCC (Voltage gated calcium channels)

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9
Q

What state are the Voltage gated Sodium channels in when they get blocked by drugs?

A

Open (Depolarised)
Inactivated

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10
Q

What drug is often used to treat Epilepsy?

A

Lamotrigine
Phenytoin

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11
Q

How does Lamotrigine help treat epilepsy?

A

Allows normal levels of CNS by preventing over firing of AP

Blocks the central pores of VGSCs while open or inactive preventing excess Na+ influx

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12
Q

What drug is often used as a local Anaesthetic?

A

Lidocaine/lignocaine
Bupivacaine (Longer half life than lidocaine)

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13
Q

How does Lidocaine act as a local anaesthetic?

A

Blocks central pore of VGSCs while open/depolarised or while inactivated

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14
Q

What drug can help treat chronic pain by blocking VGSCs?

A

Lamotrigine

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15
Q

What Voltage gated ion channels can be targeted by drugs to help treat Hypertension?

A

Voltage gated Ca2+ Channels (VGCCs)

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16
Q

How does drug blocking of VGCCs on vascular smooth muscle help treat hypertension?

A

Blocked VGCCs means Reduced Ca2+ influx into cell
Reduced [Ca2+] intracellularly
This means less Ca2+ released for the SR
Smooth muscles of blood vessels relax = Vasodilation

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17
Q

What is a drug which acts to block voltage gated ion channels to treat hypertension?

A

Amlodopine

18
Q

What are the key roles of transporters?

A

Transporting ions and molecules
Setting up and maintaining electrochemical gradients
Important in acting as an energy source for 2º active transport

19
Q

What is the energy source for 1º active transport?

A

ATP hydrolysis

20
Q

What is the energy source for 2º active transport?

A

Pre established electrochemical gradient (usually established by a Na+/K+ ATPase)

21
Q

What clinical condition is low synaptic 5-HT levels linked to?

A

Depression

22
Q

What is 5-HT also called?

A

Serotonin

23
Q

How do Selective Serotonin Re-Uptake Inhibitors (SSRIs) help treat depression?

A

It reduces the re-uptake of the neurotransmitter serotonin/5-HT
This leads to increased synaptic levels of serotonin/5-HT

24
Q

What drug is an example of a Selective Serotonin Re-Uptake Inhibitor?

A

Fluoxetine

25
Q

What do drugs that treat Diabetes Mellitus target?

A

SGLT2 (inhibitors)

26
Q

How does inhibition of the SGLT2 co-transporter in gut cells help treat diabetes Mellitus?

A

Less glucose absorbed into the blood cells and therefore into the blood reducing glucose intake

27
Q

What are the 3 possible drugs used to treat Diabetes Mellitus?

A

Dapagliflozin
Empagliflozin

Metoformin

28
Q

What is the mechanism of action of Dapagliflozin and Empagliflozin in treating Diabetes Mellitus?

A

Inhibits the SGLT2 transporters in the gut reducing glucose absorption into the body

29
Q

What is the mechanism of action for Metformin treating Diabetes Mellitus?

A

Alters cell metabolism by reducing the amount of Gluconeogenesis performed by hepatocytes
Acts against glucagon

30
Q

What are the 2 types of ways drugs can act as inhibitors to enzymes?

A

Directly:
-Competitive inhibitors
-Non-competitive inhibitors

Indirectly:
-Targets receptors that affect enzyme activity

31
Q

Where do competitive inhibitors bind to an enzyme?

A

Active site

32
Q

Where do non-competitive inhibitors bind to an enzyme?

A

Allosteric site

33
Q

What type of drugs act as Antihypertensives (treat hypertension) by acting on enzymes?

A

ACE Inhibitors

34
Q

What do ACE Inhibitors do?

A

Reduce conversion of Angiotensin I to Angiotensin II

Less Angiotensin II = Less vasoconstriction and Na+ and water reabsorption

So reduced BP

35
Q

What are some ACE Inhibitors?

A

Trandolapril
Captopril
Ramipril

36
Q

Broadly, what do Tyrosine kinase linked receptors do to other proteins to cause a cell change?

A

Phosphorylates proteins triggering a phosphorylation cascade

37
Q

What happens to a Tyrosine kinase linked receptor once a ligand binds to both separate monomers?

A

Dimer forms (Both monomers come together)
Each monomer Phosphorylates the others Tyrosine residues
Fully phosphorylated = fully active receptor
Phosphorylated tyrosines allow proteins to bind to them and transfer the phosphate to the protein
Phosphorylated protein then goes on in a cascade triggering a cellular change

38
Q

What hormone is a good example of a hormone that binds to a Tyrosine Kinase receptor?

A

Insulin

39
Q

In terms of receptors, what is abnormal about cancer cells?

A

Have many tyrosine kinase receptors which cause over activation of growth factor

40
Q

How can Herceptin be used to treat cancer?

A

Block the Tyrosine kinase receptors preventing the over expression of growth factor