Pharmacology and G proteins.
Pharmacology
Split into two main categories
Pharmacodynamics – What the drug does to the body (or cell)
How does a drug initiate an cellular response
Pharmacokinetics – What the body (or cell) does to the drug
How does a drug get from the point of administration to the cell
Pharmacodynamics is all about what happens when a drug reaches its target.
Pharmacokineteics is about the journey of the drug from its source to its target.
Pharmacodynamics in 2 steps.
Pharmacodynamics can be split into 2 steps:
How well does a ligand bind to a receptor (affinity)
And when it is bound to the receptor or protein is it then able to cause a
conformational change, activating the protein.
Converting it from an inactive state to an active state.
Some drugs may have a high affinity (they bind really well to the receptor) however
they may have a low efficacy (they may not activate a protein)
Principles of pharmacology- affinity
A ligand is never permanently bound to a receptor. It binds, performed a function,
then dissociates for the next ligand to come along
There are two options:
The ligand can be floating around in free solution- present in an unbound state (free-
ligand)
The ligand can be bound to the receptor itself- it can be present in a bound state
Receptors.
Ligands do not permanently associate or bind to receptors.
They diffuse in and out.
Depending on the ligands affinity for the receptor it will affect the time it stays.
If the ligand has low affinity for the receptor it might diffuse in and out quickly.
Ligands bind to different places on the receptor.
Ligands diffuse in and out. They do not diffuse in and stay there.
Affinity is the 1st step in signal transduction, it’s a measure of the chemical
complementarity between the ligand and the receptors binding site
E.G if ligand or hormone has positive charge on it and receptor has negative charges,
one is going to bind to the other.
If there is lots of chemical complementarity between a ligand and a receptor, this
means the ligand has high affinity.
If there is not a lot of chemical complementarity between a ligand and a receptor,
this means ligand has low affinity.
If ligand goes to wrong receptor, it will have low affinity for that receptor.
Pharmacology
Split into two main categories
Pharmacodynamics – What the drug does to the body (or cell)
How does a drug initiate an cellular response
Pharmacokinetics – What the body (or cell) does to the drug
How does a drug get from the point of administration to the cell
Pharmacodynamics is all about what happens when a drug reaches its target.
Pharmacokineteics is about the journey of the drug from its source to its target.
Pharmacodynamics in 2 steps.
Pharmacodynamics can be split into 2 steps:
How well does a ligand bind to a receptor (affinity)
And when it is bound to the receptor or protein is it then able to cause a
conformational change, activating the protein.
Converting it from an inactive state to an active state.
Some drugs may have a high affinity (they bind really well to the receptor) however
they may have a low efficacy (they may not activate a protein)
Principles of pharmacology- affinity
A ligand is never permanently bound to a receptor. It binds, performed a function,
then dissociates for the next ligand to come along
There are two options:
The ligand can be floating around in free solution- present in an unbound state (free-
ligand)
The ligand can be bound to the receptor itself- it can be present in a bound state
Receptors.
Ligands do not permanently associate or bind to receptors.
They diffuse in and out.
Depending on the ligands affinity for the receptor it will affect the time it stays.
If the ligand has low affinity for the receptor it might diffuse in and out quickly.
Ligands bind to different places on the receptor.
Ligands diffuse in and out. They do not diffuse in and stay there.
Affinity is the 1st step in signal transduction, it’s a measure of the chemical
complementarity between the ligand and the receptors binding site
E.G if ligand or hormone has positive charge on it and receptor has negative charges,
one is going to bind to the other.
If there is lots of chemical complementarity between a ligand and a receptor, this
means the ligand has high affinity.
If there is not a lot of chemical complementarity between a ligand and a receptor,
this means ligand has low affinity.
If ligand goes to wrong receptor, it will have low affinity for that receptor.
