Pharmacodynamics And Signal Transduction Flashcards
List the different types of molecular targets for drug action
Proteins
Nucleic acids
Miscellaneous targets
Give examples of different protein types that act as molecular drug targets
Ion channels
Membrane transport proteins
Enzymes
Receptors
Extracellular proteins
What types of attractive forces are at play during the binding of a drug?
Ionic bonds
Hydrogen bonds
Van der Waals forces
Why do covalent bonds not contribute to drug binding?
Covalent bonds are most often too strong and tend to lead to irreversible bonds, not necessary for drug action
What causes the attraction in ionic bonds?
One atom will donate an electron (Na) while another atom will accept the electron (Cl) the Na will become positive (Na+) while the Cl become negative (Cl-).
This is called an electrostatic attraction.
What cause the attraction between covalent bonds?
Instead of electrons being donated/ accepted they are shared between the two atoms (HCL).
These can exist as single, double or triple bonds - the more shared electrons the stronger the bond.
Explain why drug administration can be very important.
The activation/ inhibition of the same molecular targets present in other tissues (not the target tissue) can cause unwanted effects.
E.G salbutamol is a drug to treat asthma, as a tablet it could also affect the heart but as an inhaler it reaches the lungs quicker and has less impact on the heart.
Why are unwanted effects common when taking drugs for a specified reason?
Drugs are ‘selective’ rather than ‘specific’
Drugs can interact with more than one molecular target but with less force of attraction (easier to break). This is more frequent with higher drug concentrations.
How do drugs target ion channels?
Blockers
Allosteric modulators
-Inhibitor
-Facilitator
How do blockers in ion channels work?
The pore of the channels is physically blocked by the drug (e.g. lidocaine), this is in the effort to reduce pain.
Describe what allosteric modulators are?
They cause the shape of the channel protein to change to change by binding to a site on the protein that is not the active site.
They affect the responsiveness of the channels and the time for which the channel is open.
What is the difference between inhibitor modulators and facilitator modulators?
Facilitator allows more ions into the cell to increase the response.
Inhibitor reduces the amount of ions that enter the cell to lower the response.
Give an example of a inhibitor modulator
Amlodipine
Target - Ca2+ channels
Increased dilation of blood vessels, decreased BP, relaxes coronary smooth muscle and increases myocardial oxygen supply
Give an example of a facilitator modulator.
Diazepam
Target - GABAa chloride channels
Causes hyperpolarisation of the cells, decreases neurological activity, decreases anxiety and insomnia.
How do drugs target membrane transport proteins
Inhibitor
False substrates
