Introduction to receptors Flashcards
Define pharmacology.
The study of the effects of chemical substances on the function of living systems in relation to their therapeutic value - it involves aspects of physiology and chemistry.
What are drugs?
- Chemical substances of known structure other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect.
- They can be synthetic, from plants, animals or from genetic engineering.
What are medicines?
- Chemical preparations is a chemical preparation, which usually, but not necessarily, contains one or more drugs
- Administered with the intention of producing a therapeutic effect.
- Medicines usually contain other substances (excipients, stabilisers, solvents, etc.) besides the active drug, to make them more convenient to use.
What is pharmacokinetics?
How an organism reacts to a drug/processes the drug, absorption, distribution, metabolism and secretion.
What is pharmacodynamics?
How the drug affects the organism.
Who introduced opium and mercury into medicine for the first time?
Paracelsus.
What natural substances were involved in pharmacology before the 19th century?
- Quinine (malaria)
- digitalis (heart failure)
- atropine (pupils dilate)
- ephedrine (active principle of herb ‘ma-huang’).
What are the two main theories of neurotransmission?
The electrical theory and the humoral theory.
What are the main points of the electrical theory?
- Electrical current from a large muscle mass may excite a nerve.
- Effect should be bi-directional.
- However, the current in the nerve is too small to excite a muscle; amplification required.
- Amplification occurs at the nerve/muscle junction and is achieved chemically.
What are the main points of the humoral (chemical) theory?
- Transmission across the gap is uni-directional.
- Delay in transmission across the gap.
- Fatigue occurs more readily at junctions.
- Drugs may act selectively at synapses/junctions.
What did Schmiedeberg discover?
Muscarine (found in certain toadstools) can stimulate the vagus nerve of the heart - decreasing heart rate. (vagul stimulation)
What synthetic drugs appeared in the 20th century?
Barbituarates, local anaesthetics, antimicrobial chemotherapy and antibacterials.
What did Paul Ehrlich do?
Studied effect of dyes on bacteria
What did Henry Dale do?
Conducted studies on histamine and acetylcholine.
What did Henry Dale discover?
Noticed Ach was equipotent with muscarine.
Also, that Ach mimicked parasympathetic nerve stimulation and that low doses of Ach were blocked by atropine, but high doses mimicked the effects of nicotine (stimulation of sympathetic ganglionic cells).
