Lecture 3 Flashcards
What is the difference between pharmacology and pharmacy?
Pharmacology: Study of mechanics by which drugs (biologically active compounds) affect the function of living systems.
Pharmacy: Study of formulation, dispensing and dosing
What are receptors?
Proteins which recognize and bind ‘chemical mediators/ messengers’
What are examples of chemical mediators?
hormones, neurotransmitters, antibodies
What is the main function of receptors?
regulation of cellular processes
What are the two types of cellular processes?
- hormone recognition and binding
2. intracellular signal generation
What are current proteins targeted by small molecule drugs?
- ST/Y kinases 22%
- GPCRs 15%
- Cation channels 5%
- Ser proteases (trypsin) 4%
- Protein phosphatases 4%
How much of drugs interfere with the function of receptors involved in chemical communication?
40%
What are subclasses of receptors classified by structure?
- carriers/transporters
- enzymes
- ion channels
How many types of receptors are there?
1000
What is an example of receptors that bind to different ligands?
Muscarinic ACh receptors
Ligands: ACh and nicotine
What is an example of an accessory protein that binds to enzymes?
ATP
What are drugs that bind to a receptor producing a response by mimicking the effect of chemical mediators?
Agonists
What are examples of agonists?
Morphine, pilocarpine
What is a poppy derived drug that interacts with pain-sensory neurons which mimics endorphins.
Morphine
What is a side-effect of morphine?
Addiction from constant stimulus
What does pilocarpine bind to?
Muscarinic ACh receptors in ANS
What is an antagonist?
Drugs that prevent the response of an agonist
What is an example of an antagonist?
atropine
What is atropine an antagonist to?
pilocarpine
What are examples of drugs which target ion channels?
Lignocaine, apamin, nifedipine ariloride
Where is lignocaine found in?
Strepsils
What is lignocaine?
Local anesthetic
How does lignocaine work?
Binds to voltage gated sodium channels to stop their activity and prevent pain information inflammation, then pain nerve ending activation doesn’t reach CNS.
Where is apamin found?
bees
How does apamin work?
Blocks activity of voltage gated potassium channels so that pain nerve endings fire more AP
What type of substance is nifidepine?
dihydropyridines
What does nifidepine do?
Counteracts hypertension
How does nifidepine work?
Blocks voltage gated calcium channels in smooth muscle lining arteries which reduces resistance to bring down hypertension
Where does ariloride (an ENAC) work?
Kidneys
What are examples of drugs which target enzymes?
acetylsalicylic acid, pargyline (and clorgyline), captopril
Where is acetylsalicylic acid found?
aspirin
Which enzymes does acetylsalicylic acid target to?
COX and MAO
What does COX do?
Reduces pain associated with inflammation
What does MAO do?
Breaks down noradrenaline, adrenaline
What does Pargyline do?
Inhibits MAO against hypertension as a treatment against depression
Where does pargyline affect?
CNS - unwanted side effects in CNS and PNS cannot be
What is captopril?
ACE inhibitors
What is captopril used for?
Treatment for hypertension
How does captopril work?
Increases angiotensin by acting on an enzyme
What are types of drugs that target transporters?
- some need ATP and some need solutes
- prevents action potential
- may be hijacked and transport is utilized to get into cells
What are examples of drugs that target transporters?
fluoxetine (prozac), Digoxin
What is fluoxetine (prozac)?
It is a widely prescribed antidepressant more specific to the CNS
What transmitters does fluoxetine target?
5-HT, serotonin
How does fluoxetine work?
It blocks transport of serotonin so that it builds up outside of neurons to ctivate receptors for happiness
Where is digoxin found?
In foxgloves
What transporter does digoxin target?
Na/K transporter (exchanger)
How does digoxin work?
- Na in heart muscle builds up
- Ca builds up in heart
- Strength of contractility increases
- Prolongs action potential
What is a receptor superfamily?
Receptors which have similar structural features
How many receptor superfamilies are there?
4:
Ligand-gated ion channels (ionotropic receptors)
G-protein-coupled receptors (metabotropic receptors)
Kinase-linked receptors
Nuclear receptors
Which receptor superfamilies are found on the cell surface?
All except nuclear receptors
How many hydrophobic amino acid segments are there in transmembrane spanning receptor proteins?
20-25
Many drugs act via the _ domain.
ligand binding
Nuclear receptors are DNA-linked. What does this mean?
They regulate gene transcription and the ligand must be able to cross the plasma membrane
