Intro to Pharmacology Flashcards
What is pharmacology?
The study of drugs and how they interact with living systems
- what drugs do to the body
- What the body does to drugs (this is important for drugs that are orally administered as they need to be absorbed and metabolised)
What is a drugs ‘Therapeutic Index’?
The does of drug needed for desired clinical and therapeutic effect
What are drugs defined as?
Any substance what when administered produces a therapeutic effect
- Man-made
- Natural
- Endogenous
What is an endogenous drug?
Originates within e.g. hormones
What is Pharmacodynamics?
What drugs do to the body
How do drugs interact with a target to induce a therapeutic effect?
Chemically: typically through binding to proteins in cell membrane to induce a cellular response
How do cells communicate?
Through chemical signals that regulate cell function
How many breakdowns in cellular communication do all diseases involve?
At least 1
What are the breakdowns in communication that can occur between cells?
- Loss of signal
- Failure to respond to a signal
- Failure of signal to reach target
OR multiple breakdowns can occur
Give an example of a condition affected by the loss of the signal by cells?
- Type 1 diabetes
- Process: After food enters the body, it is broken down and sugar enters the blood stream. Sugar stimulates cells in the pancreas to release insulin. Insulin travels through the blood to other cells in the body and signals them to take up sugar
- If a patient has type 1 diabetes then no insulin is produced and this process cannot occur
What is the treatment for Type 1 diabetes?
- Replenish insulin (can be done by injecting it into patient)
- NOT a cure but maintains blood glucose levels within healthy limits
- Patients may also take immune-modifying drugs to limit further beta-cell destruction
Give an example of a condition that occurs when the target ignores the signal?
- Type II diabetes
- The receptor is desensitised and so switches off the signal pathway
- This is associated with poor diet and lack of exercise
What is the treatment for type II diabetes?
- Diet and exercise to regulate blood glucose
- Metformin:
- Accumulates in hepatocytes (liver cells)
- Reduces amount of sugar released into blood
- Increases insulin receptor expression - partial improvement in glucose uptake
Give an example of a condition that occurs when a signal doesn’t reach the target?
- Multiple Sclerosis
- Loss of the myelin sheath on neurones
What is the treatment for Multiple Sclerosis?
- Use of steroids and immune-modifying drugs to prevent/limit cell destruction
Give an example of a condition that occurs when there are multiple breakdowns in communication in cells?
- Cancer
- Despite tight controls breakdown in cell communication can lead to uncontrolled cell growth
- This often occurs in the absence of a signal which leads to apoptosis BUT if the cell loses ability to respond to death signals it divides out of control
What are the possible treatment options for cancer?
- There are many but it depends where, how big and have they spread?
- Surgery: Mainstay of cancer treatment to remove damaged cells
- Chemotherapy: Systemic administration of one or more anti-cancer drugs
- Radiotherapy: Radiation damages DNA in cancer cells
- Immune therapy: Monoclonal antibodies which is targeted immune therapy
- Vaccines
What is meant by ligand/receptor interactions being HIGHLY SPECIFIC?
- One ligand binds to one receptor
- One receptor binds to one ligand
What are receptors usually made of?
Trans-membrane proteins
What are the 3 classes of membrane receptor?
- G-protein coupled receptor
- Enzyme-linked receptor
- Ion channel receptors
What is the largest and most diverse group of membrane receptors?
G-protein coupled receptors
What percentage of drugs act by binding to G-protein coupled receptors?
30%-50%
How do enzyme-coupled receptors function?
- When ligand binds to receptor, the 2 arms of the receptor can come together (conformational change) which activates the enzymes within receptor - activation done by phosphorylation which can switch on/off the receptor
What do ion-channels convert chemical messages into?
Electrical messages
What 2 types of ion channel are there?
- Ligand-gated
- Voltage-gated
What is signal transduction?
- Chain of biochemical reactions that occur in a cell to transfer a signal:
- Phosphorylation (modifies protein activity)
- Second messengers (small non-protein molecules)
- Action potentials (mediated by ion influx)
What is the function of signal transduction?
Amplifies the signal and delivers the signal to effector proteins which mediate the cellular response
What are the 2 possible MOLECULAR level cell responses?
- Regulation of gene expression (nucleus)
- Regulation of cellular metabolism (cytoplasm)
What are the possible MACROSCOPIC level cell responses?
- Differentiation, proliferation, migration, apoptosis
- Cell fate ‘decisions’ based on integration from multiple inputs
Why are signalling pathways hugely complex?
They are integrated and often converge
What is a transcription factor?
A protein that binds to DNA to regulate gene transcription
Do all or cells contain the same genetic information?
Yes, however how this information is deployed gives rise to the structural and functional diversity of cells found in mature organisms
- Communication between cells allows for specialisation of groups of cells
How do proteins, encoded by genes, dictate cell structure and function?
- Only a fraction of genes in a cell are expressed 1. at any one time and 2. throughout a cells lifetime
- Different types of cells express different proteins
- These proteins dictate what the cell type is, that it can do and the signals it can detect and respond to
What is the name given to a drug that acts to stimulate the normal cell communications?
Agonist
What is the name given to a drug that acts to inhibit normal cell communications?
Antagonist:
- competitive
- non-competitive
What is meant by drug absorption?
How the drug reaches the circulation
What is meant by drug distribution inside the body?
- Where the drug goes to in the body - the solubility and body’s interactions wit the drug
- There is usually a non-uniform distribution
What is meant by drug metabolism inside the body?
- Is the drug activated or deactivated in the liver?
What is meant by drug excretion by the body?
- How the drug leaves the body
- Main route is via the kidneys
What happens if you administer too much drug?
Can have harmful effects
What happens if you administer not enough drug?
Can be weakened effect or no effect
