Lecture 29 - Introduction Flashcards
(26 cards)
What is a drug?
A chemical of known structure, other than a nutrient or essential dietary ingredient, that produces an effect when introduced to a biological system.
Thiazide diuretics:
1)
2)
3)
1) Inhibit Na+/Cl- cotransporter in renal distal convoluted tubule.
2) Increase Na+ and water excretion from distal convoluted tubule.
3) Lower blood volume, blood pressure.
Pharmacodynamics
Effect of a drug on the body
Pharmacokinetics
Effect of the body on a drug
Acetylcholine nicotinic receptor timeframe
Miliseconds
Adrenoceptor timeframe (GPCR)
Seconds
Tyrosine kinase receptor timeframe (Insulin)
Minutes
Nuclear receptor timeframe (cortisol)
Hours
D-tubocurarine effect
Prevents muscle contraction
D-tubocurarine binding
Binds ACh receptors on nicotinic Na+ ion channels
Physostigmine target
Acetylcholineesterase
Aspirin target
Cyclo-oxygenase
Cyclo-oxygenase role
Makes inflammatory prostaglandins
Imatinib target
BCR-abl tyrosine kinase
Disease associated with BCR-abl
Chronic myeloid leaukaemia
Receptor associated with insulin
Tyrosine kinase
Cortisol receptor
Glucocorticoid receptor
Ways to control chemical signalling:
1)
2)
3)
1) Breakdown of signalling chemical
2) Reuptake of chemical signal
3) Negative feedback
Example of breakdown of signal molecule
Acetylcholine/acetylcholineeserase at NMJ
Example of reuptake of chemical signal
Noradrenaline, reuptaken into sympathetic nerves
Example of negative feedback
Insulin
Example of direct feedback
Cortisol
Method of insulin negative feedback: 1) 2) 3) 4)
1) Increased glucose levels in pancreatic beta-cells increases ATP levels.
2) Metabolism-steered K+ channels blocked by ATP.
3) Cell depolarises, opening voltage-gated Ca2+ channels.
4) Insulin released.
Method of cortisol action:
1) Cortisol binds to glucocorticoid receptor in cytoplasm, chaperone unbinds.
2) Receptor-cortisol complex enters nucleus, binds ligand on DNA.
3) Changes gene expression.