Fatima Adam
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Why is it important to understand receptors? Give 4 reasons.
1)Pharmaceutical industry and development: 34 of the top 100 drugs on the market target G-protein couples receptors
2)Physiology of endogenous transmitters: Transmitters and hormones act primarily upon receptor targets
3)Chemical toxicity: Many toxic mechanisms are receptor mediated
4)Viral toxicity: Viruses and other microorganisms can target receptors
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What is an agonist?
Drugs that occupy receptors and activate them
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What is an antagonist?
Drugs that occupy receptors but do not activate them, antagonists block receptor activation by agonists
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What is a partial agonist?
Drugs that can occupy receptors and activate them but not to the extent of an agonist
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A picture demonstrating the agonist having both affinity and efficacy:
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Statement: Most agonists bind irreversibly to their receptors.... Is this true?
FALSE
-Most agonists bing reversibly to their receptors and then dissociated when unneeded
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Why is the binding reversible?
Weak bonds
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Name the 4 main bonds and describe their strengths and dissociations
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Reversible binding of an agonist to a receptor is governed by what law?
Law of mass action
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Picture demonstrating how reversible binding is dependent on concentration of the reactants involved
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What is the Bmax?
The maximum amount of receptor binding
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Each drug has its own what value?
Kd value
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What is Kd?
Kd (Affinity) is the ability of a drug molecule to bind to a receptor site: Concentration of the drug where 50% of max number of receptors are bound by the drug
Kd is inversely correlated with affinity. The lower the Kd, the higher the affinity
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What is Efficacy?
Refers to the effect of the drug/ the biological effect, the more effect the drug has the more efficacious. e.g. increase in heart rate
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Picture outlining efficacy:
