Pharmacology, drugs etc Flashcards
What is pharmacology?
Pharmacology is the scientific study of drugs and their effects on living organisms
What are the key features of a drug?
1:Chemical Structure:
Defined molecular composition.
Example: Caffeine (molecular formula shown on slide).
2:Physiological Response:
Drugs produce specific effects on the body.
Example: Caffeine acts as a CNS stimulant.
3:Physiological Targets:
Drugs interact with specific biological targets.
Example (Caffeine):
Adenosine Receptors: Blocks these to prevent drowsiness.
Modulates GABA activity.
Influences Phosphodiesterase enzymes.
What is pharmacodynamics? PD
Focus: What the drug does to the body.
Key aspects:
Drug action.
Mechanisms of drug effects at the molecular, cellular, or organ level.
What is pharmocokinetics, PK
Focus: What the body does to the drug.
Key processes (ADME):
Absorption: How the drug enters the bloodstream.
Distribution: How the drug is transported in the body.
Metabolism: How the drug is broken down, often in the liver.
Excretion: How the drug is eliminated from the body, primarily via the kidneys.
What is the difference between pharmacokinetics and pharmacodynamics?
Pharmacokinetics determines drug concentration at the site of action.
Pharmacodynamics determines the drug’s therapeutic and side effects.
What is specificity?
The ability of a drug to elicit a targeted physiological response by acting on the “right target.”
What is chemical specificity?
Refers to a drug’s ability to interact with the “right target binding site” based on its molecular structure
What is the difference between biological selectivity vs chemical specificity?
Biological Selectivity: Ensures the “right target” is activated.
Chemical Specificity: Ensures the drug fits perfectly into the binding site to elicit desired responses with minimal side effects.
What are the key drug binding sites?
- Enzymes
- Transporter
- Ion channels
- Receptors:
Ligand-gated ion channels (ionotropic receptors)
G-protein-coupled receptors (GPCRs, metabotropic receptors)
Catalytic/tyrosine kinase receptors
Nuclear receptors/transcription factors
What are some drugs targeting enzymes examples? include the process name, enzyme used and drug
intracellular breakdown → phosphodiesterase → sildenafil
Neurotransmitter degradation → acetylcholine esterase → neostigmine
Messenger synthesis → cyclo-oxygenase → ibuprofen (reversible) or aspirin (irreversible)
What is entailed in non-competitive binding?
Mechanism: The drug binds at a site different from the active site of the enzyme, causing a conformational change that reduces enzyme activity.
What is entailed in competitive binding?
Mechanism: The drug competes directly with the natural substrate for the active site of the enzyme.
What is the difference between competitive/ non comp binding?
Non-competitive inhibitors affect enzyme function regardless of substrate concentration.
Competitive inhibitors rely on higher drug concentrations to outcompete the natural substrate.
What happens in noradrenaline uptake in the left panel?
Normal Transporter Function (Left Panel):
Noradrenaline Transporter (NAT):
Responsible for reuptaking noradrenaline from the synaptic cleft back into the presynaptic neuron.
This process terminates the action of noradrenaline at the receptors, leading to a regulated and limited response.
What happens in noradrenaline uptake in the right panel?
Blocked Transporter Function (Right Panel):
Cocaine and TCAs (Tricyclic Antidepressants):
Mechanism: These drugs inhibit the noradrenaline transporter (NAT), preventing the reuptake of noradrenaline.
Effect:
Increased noradrenaline levels in the synaptic cleft.
Prolonged and enhanced stimulation of post-synaptic receptors.
Results in amplified physiological responses.
