FOM Flashcards
What is homeopathy?
- giving medicine which contain no medicine
- recognise patients may choose complimentary and alternative medicines
What is a drug?
- most drugs are chemically inert
- momentarily bind to command and control molecules in the body
- molecular structures are complementary receptors
What is an agonist?
- binds to receptor and activates it signalling to produce a response
What is affinity of a drug?
- extent to which a drug binds to its receptor at a given concentration
What is the intrinsic activity of a drug?
- ability of drug to illicit an effect
What does having a wide therapeutic index mean?
- very few people taking effective dose will experience toxic effects
What is an antagonist?
- prevents response from occurring
- competitive and non-competitive
- has affinity for binding to receptor but does not evoke a response
- no efficacy/intrinsic activity
What is the effect of competitive antagonist on potency?
- agonist has less potency
Why is non-competitive antagonist irreversible?
- permanently bind on allosteric site
- no amount of agonist can compete and reverse effect
- effect stops when receptor is replaced or recycled
What is pharmacological antagonism?
- antagonist acts at same target receptor as agonist
What is a partial agonist?
- cannot produce a maximal response even when occupying 100% of receptors
What are non-receptor drug targets?
- ion channels
- enzymes
- transporters
What is tachyphylaxis?
- on repeated administration some drugs need increasing doses for same effect to occur
What are the types of receptors found in PNS nervous system?
- pre-ganglionic: nicotinic
- post ganglionic: muscarinic
What are the types of receptors found in SNS?
- preganglionic: nicotinic
- postganglionic: adrenergic with exception of sweat glands and adrenal medulla
Where are the nicotinic receptors located?
- at the ganglion
- at muscle type
Describe nicotinic receptors
- ligand-gated ion channels: ionotropic
- alpha 3 subunit allows binding of Ach
- binding of 2 Ach molecules to alpha subunits open pores and allow Na to flood into cell
What does stimulating ganglionic and muscle type nicotinic receptors do?
- bronchoconstriction and mucus secretion
Describe muscarinic AChr
- found at PNS post ganglionic neurone
- GPCR
- binding causes G alpha to swap GDP to GTP
- G alpha dissociates from complex activating downstream effector molecules
In the SNS, what are most post ganglionic nerves mediated by?
- noradrenaline
What does stimulating the different adrenergic receptors do?
- B1: increase heart rate
- B2: bronchodilation through binding of adrenaline
- A2: break down of noradrenaline. inhibit release of neurotransmitters
- A1: decrease nasal secretions. by constricting blood vessels
Where is the A2 receptor found?
- on pre-synaptic cells
What are the exceptions in the post-ganglionic nerves of SNS?
- sweat glands: release ACh binding to muscarinic AChR
- adrenal medulla: interact directly with gland signalling release of adrenaline.
What do agonists of muscarinic receptors do?
- mimic ACh. Increased effects of rest and digest
