Lecture 2 Flashcards
(32 cards)
How do dugs act?
Receptors are molecular targets for most drugs
Drug + Receptor ——> drug - receptor complex which leads to the physiological response
Name physiological responses
Increase in temp Decrease in blood pressure Contraction of muscle Secretion of hormone Growth Increase in sugar levels Heart rate
What can drug action be?
Specific and non specific
Name the different protein targets
Receptors Ion channels Enzymes Carrier proteins DNA for cancer therapeutics
Give some information about the cell membrane and receptors
Most common site for receptors are on the cell membrane or on the nucleus. Receptors for steroids are located inside the cell.
Give some information about asthma patients
In asthma the air pipes are narrower and breathing is constricted. Contraction of the smooth muscles means that medication is needed to open up the airways. For example salbutamol, an inhaler is taken and the airways open up and muscles relax so it is easier to breathe. The blue inhaler is a reliever and should be taken as soon as you feel a tight feeling in the chest or breathlessness. The brown inhaler is a steroid inhaler and should be taken every day, it is important not to miss this dose because it takes longer to work as the receptors are inside the cell so takes longer to work.
What are receptors?
Receptors are transducers capable of converting the energy from environmental stimulus into nerve impulses
Name the 5 receptor classifications
Selective agonists Selective antagonists Ligand binding Transduction pathways Molecular structure
What is an agonist?
An agonist is a drug which is capable of interacting with a receptor and binding to it and activating it to cause a response
What is an antagonist?
An antagonist is a drug capable of binding to receptors, but not activating it and then blocking the action of the agonist
What is histamine?
A naturally occurring chemical in the body which is released by the body during an allergic reaction or inflammation
Give the example of hay fever
Hay fever is an allergic response to pollen which causes a runny nose, itchy eyes and a cough. Antihistamines are used to combat the symptoms which reduces the allergic response. The antihistamine binds to the histamine receptors. The antihistamines are antagonists for the histamine receptor.
What is the h1 receptor?
Blocked by the antihistamine to reduce allergic response and inflammation
What is the h2 receptor?
Blocked by the antihistamine to treat peptic ulcer
Explain ion channels
Pores on the cell membrane can open/close to allow or prevent the passage of ions down the conc gradient
Name three drugs which act on ion channels
Benzodiazepines, verapamil and lignocaine
What does benzodiazepine do?
It is an anti anxiety and anti convulsant agent. It increases the conductance of chloride ions by increasing the frequency of chloride channel opening. This means the inside of the cell is more positive than the outside of the cell which means the cells are less likely to be excitable and the anxiety symptoms are reduced.
How does verapamil work?
It is a calcium channel blocker used for patients with heart problems. Calcium is important in the contraction if muscle. Typically used in patients with angina or Arrhythmias. They inhibit the entry of calcium into cardiac and muscle cells which leads to a reduction in contraction.
Lignocaine
Local anaesthetics exert action by blocking the sodium channel
Where are cattier proteins located?
Located on the cell membrane or intracellular organelles and they transfer materials against their conc gradient using active transport and ATP
What are examples of carrier proteins?
Sodium pump - pumps out Na+ and K+ into cells by using ATP. The action of the pup can be inhibited by cardiac glycosides
Sodium chloride co-transporters in kidney can be inhibited by thiazide diuretics and loop diuretics
What are enzymes?
Enzymes are molecular proteins which catalyse or speed up the rate of a chemical reaction in the organism
How do enzymes and drugs work?
Drugs can bind to enzymes and inhibit or interfere with their action
Give the example of aspirin?
Aspirin is used for pain relief, thinning blood and anti-inflammatory action. It effects the enzymes that is responsible for inducing inflammation mediators (prostaglandins) in the body, inhibits the COX enzyme
