PHARMACOLOGY - Basics Flashcards
inositol triphosphate is activated by what? what is its pathway?
activated by alpha one adrenoceptors. Binds to endoplasmic reticulum membrane, increases concentration of intracellular calcium –> smooth muscle contraction –> ++ exocrine secretion and force/rate of cardiac contractions
What are the actions of the parasympathetic pathway? (2)
- Ciliary muscle contaction –> accomodation
- Sphincter muscle constriction –> constriction
What are the actions of the sympathetic pathway?
- Ciliary muscle relaxation
- Dilator pupillae action –> mydriasis
- Upper lid retraction (Dalrymple sign)
Where are Beta-2 receptors found? (3)
Lungs, GI tract, vascular smooth muscle
What is the systemic effect of leukotrienes? (3)
- Bronchoconstriction
- Vasoconstriction
- Increase vascular permeability
–> involved in allergic reactions and inflammation
What is Fick’s Law?
Movement of particles from high to low concentration (diffusive flux) is directly proportional to the particle’s concentration gradient
rate of diffusion = diffusion coefficient x (concentration gradient / membrane thickness)
Which drug can cause xanthopsia (yellow-blue discoloration), photopsia and pain on eye movements?
digoxin
Accomodation occurs with parasympathetic or sympathetic control?
parasympathetic control
What effects happen with beta-2 blockers?
- Bronchoconstriction
- Peripheral arterial constriction
- Reduced aqueous production from ciliary epithelium
What are the general ocular actions of adrenergic agonists (4)
- Increase aqueous outflow
- Ciliary muscle relaxation
- Contraction of Muller’s muscle –> reversal ptosis
- Conjunctival vessel constriction
What are some examples of G-protein receptors? What are some examples of ligand gated ion channels?
G-protein
Muscarinic Receptors
Adrenergic Receptors
Ligand gated ion channels
5HT3 receptors
GABA receptors
What are the main neurotransmitters in the parasympathetic nervous system? (1)
Acetylcholine
What receptors does ACh act on?
- Muscarinic (G-protein coupled) usually post-ganglionic acting at effect organs
- Nicotinic (ligand-gated) usually at synapses and neuromuscular junction
What are the main neurotransmitters in the sympathetic nervous system? (3)
- ACh (autonomic ganglia)
- Adrenaline
- Noradrenaline
How are adrenaline and noradrenalin signals terminated?
Terminated by
1. presynaptic reuptake
2. degradation by COMT and monoamine oxidases
Ciliary body relaxation is caused by which pathways?
- Adrenergic agonists (sympathetic)
Memorable facts of ACh
Remember that acetylcholine is the major neurotransmitter in the parasympathetic system and acts on two types of receptors, nicotinic and muscarinic receptors. Nicotinic receptors are usually located at ganglion synapses and at neuromuscular junctions. Muscarinic receptors are situated at the effector organ (post-ganglionic). The main mechanism in which acetylcholine is metabolised is by hydrolysis, either within the synapse by acetylcholinesterase or it is absorbed into plasma then undergoes hydrolysis by butyrylcholinesterase.
What are the effects of alpha-1 adrenergic receptors?
- Vasoconstriction
- Increased peripheral resistance (blood flow)
- Increased blood pressure
- Mydriasis
- Closure of bladder sphincters
What are the effects of alpha-2 adrenergic receptors?
- Inhibits norepinephrine release
- Inhibits Acetylcholine release
- Inhibits insulin release
What are the effects of beta-1 adrenoceptors? (4)
- Increase heart rate
- Increase lipolysis
- Increase myocardial contractility
- Increase RENIN
What are the effects of beta-2 adrenoceptors? (6)
- Vasdilation
- Reduced peripheral resistance
- Bronchodilation
- Increased glycogenolysis
- Increased glucagon release
- Relaxes uterine smooth muscle.
MEMORISE THIS TABLE.
Where are the muscarinic receptors in the eye and what do they activate?
Which are the common P450 inhibitors ?
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Sodium valproate
Isoniazid
Cimetidine
Ketaconazole
Fluconazole
Alcohol
Chloramphenicol
Erythromycin
Sulphonamides
Ciprofloxacin
Omeprazole
Metronidazole
Grapefruit Juice
What are the common P450 inducers?
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Carbamazepines
Rifampicin
Alcohol (chronic)
Phenytoin
Griseofulvin
Phenobarbatone
Sulphonylureas
What are the different muscarinic receptors and what do they activate (systemically)?
LOCATION, AGONIST ACTION, ANTAGONIST ACTION
M1, M4, M5 - CNS
M2 - heart
M3 receptor locations:
AEIOU: airway, exocrine , eye, O (gut), urinary tract