Principles Of Pharmacology 1 Flashcards by Ghosn Al-Khulaidi

What is the need for receptors?

Signalling molecules or hormones in the blood reaching a large no. Of cells

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Do all cells respond to receptors?

Specificity is applicable where only specific cells have receptors for that chemical.

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What is the receptor concept?

Chemicals produce and effect by combining to specific receptor - lock and key model.

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What is affinity?

The strength of a drug receptor interaction

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What are receptors?

Proteins with specific binding site that has both affinity and receptive to ligand

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Receptor locations

Name different receptor locations

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What are the four types of receptors?

Ion gated channels, g protein couples receptors, kinase linked receptors, nuclear receptors

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How to ion gated channels work?

Hyperpolarisation/ depolarisation affects ion gates whether they open or close

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How do G PC receptors work?

Upon activation by a ligand, the receptor binds to a partner heterotrimeric G protein and promotes exchange of GTP for GDP

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How do kinase linked receptors work?

play an important role in protein phosphorylation, gene transcription, protein synthesis and cellular effect

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How do nuclear receptors work?

Change what type of gene is expressed or depressed

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List transmitters?

Hormones, neurotransmitters, autocoids, neuropeptides, neuromodulators

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What are hormones?

Released from one cell to an extracellular cell to travel to new site if action

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How are neurotransmitters released?

By exocytosis

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Name types of neurotransmitter degradation and recovery

Diffusion- away from synapse /reuptake- nt reenter presynaptic axon terminal/ enzymatic degradation - in cytosol or synaptic cleft

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Give types of neurotransmitters:

Acetylcholine, monomanies such as noradrenaline and dopamine/ amino acids such as GABA and GLUTAMATE/ neuropeptides such as endorphins/ purines such as ATP / soluble gases such as nitric acid

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Give amino acid types of neurotransmitters and their functions?

GABA- 40% inhibit
GLUTAMATE- 50% excite

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Whats the difference between a hormone and neurotransmitter?

N- diffused from presynaptic cleft into extracellular space to act in adjacent neurones
H- chemical released by an organ to be transportd in blood to reach targetted organ/tissue

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Difference between adrenaline and noradrenaline

Adrenaline is a hormone released in blood for fight or flight and noradrenaline is a neurotransmitter

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Recall types of receptors based on ligand

Cholinoreceptors- muscarinic and nicotinic
Histamine- h1/h2h3
Adrenoreceptors- alpha and beta

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What are the different acetylcholine receptors

Muscarinic and nicotinc

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Tell me more about nicotinc receptors

Ligand gated ion channels permeable to na+ ions and are excitatory
They are pentaremic and have 5 sub units alpha beta etc.

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Tell me more about muscarinic recrptors

G protein coupled receptors, with 5 subtypes, M1/3/5 excite and M2/4 inhibit

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What are gluttamate receptors

Theyre both ionotropic and metabotropic

What are ionotropic receptors?

Receptors that open cation channels

Talk about Gaba receptors

Gaba a- ionotropic- chloride channel Gaba b - metabotropic - stop voltage gated ca channels and open k channels

What are G coupled protein receptors

Muscarinic alpha beta receptors work by turning on transducer proteins specifically guanine

Structural motifs

7 hydrophobic channels, single polypeptide chain with extracellular n terminus and intracellular c terminus

What does an active g protein interact with

Ion channel to allow influx of ion or enzyme to produce a substance that helps to make another thing known as second messenger

Whats the role of an agonist

Cellular response

Whats the role of an antagonist

No response

Explain the role of a pharmacological agonist

Combines with receptor and produces a response so has efficacy and affinity

Explain the role of an antogonist

Combines with receptor does not cause a response but prevents agonist binding Has affinity but no efficacy

Whats the difference between blocker and modulator?

Blocker permeation is blocked whereas modulator increased/ decreased probability of opening

What effect does a substrate have on enzyme?

Normal reaction =normal metabolite produced

What effect does inhibitor have on enzyme?

Normal reaction inhubitted

What effect does false substrate have on enzyme

Abnormal metabolite produced

What does effect does prodrug have on enzyme

Active drug produced

How do you study the effects of a drug on a receptor?

Use an isolated tissue preparation within an organ bath and investigatethe effects of the addition of the drug OR Use an animal/human and give them an increasing dose of the drug and monitor particular effect

What information does the EC50 provide to us?

If drug had low EC50, drug has high affinity If drug has high EC50, drug has low affinity

How should a drug with different affinity be used in terms of dosage

If a drug has high affinity it should only be used in low concs and if a drug has low affinity it should be used in high concs

How do you determine EC50?

By looking at the drug response at 50 and noting down the antilog

Define EC50

The affinity of an agonist for its receptor

In humans do we use affinity or potency

Potency

Define potency

The required amount of drug to gain particular effect in an intact animal

What is the amount of drug in relation to effect?

Some drugs have different potency but will have same efficacy

On a graph, how do you know that all receptors have bound?

Maximum response of curve has levelled off

What are the different types of agonist

Partial Full

What does 100% occupancy mean

100% effect

What is drug efficacy

The ability of drug to produce a therapeutic effect

What is the intrinsic activity equation

Maximum response to TESTagonist/maximal response to FULL agonist

How do you calculate intrinsic activity

Small h/H

What are the theee types on antagonist

Chemical, physiological, pharmacological

What is a chemical antagonist?

A drug that counters the effects of another by binding the agonist drug (not the receptor)

What is a physiological antagonist

Where the effect of the drug starts a reaction opposite to what is currently happening Does not act at same receptor site Usually pharmacological agonist

What is a pharmacological antagonist?

Agonist meets receptor to stop action of agonist DOES NOT CAUSE A RESPONSE

What is a irreversible antagonist

Binds in irreversible manner by covalent bond modification, causing irreversible effects= agonist cannot bind Adding more agonist WILL NOT FIX THIS WILL HAVE TO MAKE NEW RECEPTORS VIA PROTEIN SYNTHESIS

What are non comp antagonists?

Binds to allosteric site, CANNOT BE OVERCOME BY ADDING MORE AGONIST May not impair binding of ligand to make complex but will cause a conformational change= response