PHARM; Lecture 1, 2 and 3 - Intro to ANS, Mechanism of Drug action (I & II) Flashcards
What are the principal target organs of the sympathetic NS?
Eye, Salivary glands, trachea/bronchioles, skin, heart, GI, Liver, adipose, kidney, ureters and bladder, blood vessels
What are the principal target organs of the Parasympathetic NS?
Eye, Salivary glands, trachea/bronchioles, heart, GI, ureters and bladder
FITB for the action of ANS on target organs
x
What transmitters are released from pre and post ganglionic fibres in sympathetic NS?
x
What transmitters are released from pre and post ganglionic fibres in parasympathetic NS?
x
What is the difference between the PSNS and SNS in terms of response?
SNS is very coordinated with a lot of divergence due to short pre-ganglionic fibres VS PSNS is discrete, localised and with little divergence
What is the difference in the innervation of the somatic NS compared to the ANS?
Somatic has a motor neurone which releases ACh then leads onto the effector skeletal muscle
What are the membrane bound receptors for ACh?
Muscarinic and Nicotinic
What kind of receptor are the nicotinic ones?
Ionotropic, and is stimulated by nicotine/acetylcholine
Where are nicotinic receptor situated?
All autonomic ganglia
What are muscarinic receptors and where are they situated?
G-protein coupled and located at all effector organs innervated by post-ganglionic PSNS fibres
What are muscarinic receptors stimulated by?
Muscarine and ACh
Which of the following effects would be observed after blockade of nicotinic acetylcholine receptors in an individual at rest? 1) Bronchoconstriction 2) Increased sweat production 3) Constipation 4) Increased urinary frequency 5) Short-sightedness
Constipation
What are the types of muscarinic receptors?
M1, M2, M3, M4, M5
What is the function of M1 receptor?
Neural - forebrain; learning and memory
What is the function of M2 receptor?
Cardiac - brain; inhibitory autoreceptors
What is the function of M3 receptor?
Exocrine and smooth muscle - Hypothalamus; food intake
What is the function of M4, M5?
M4: periphery; prejunctional nerve endings (inhibitory). M5: Striatal DA release
What are the different types of muscarinic?
x
What are the types of adrenoceptors?
Alpha 1, 2 and beta 1, 2
Where are adrenoceptors located?
All effector organs innervated by postganglionic sympathetic fibres
What are adrenoceptors and what stimulates them?
G-protein coupled and stimulated by NA/Adrenaline
Blockade of which of the following receptor sub-types would induce both an increased heart rate and a reduction in sweat production during exercise? 1) Muscarinic receptors 2) α1 adrenoceptors 3) α2 adrenoceptors 4) β1 adrenoceptors 5) β2 adrenoceptors
Muscarinic receptor
How is ACh synthesised, released and metabolised?
1) Binding of Acetyl CoA + Choline to form ACh. 2) ACh is placed in vesicles. 3) Ca2+ moves in via VSCC, so vesicle moves to membrane 4) ACh is exocytosed into the synaptic space. 5&6) ACh moves in synapse and attaches with receptor. 7) Acetylcholine esterase breaks down ACh into choline and acetate. 8) Choline is taken up and is used back up.
How is NA synthesised, released and metabolised?
x
Blockade of which of the following targets would cause the most significant rise in synaptic noradrenaline concentrations? 1) Tyrosine hydroxylase 2) DOPA decarboxylase 3) Uptake 1 transport protein 4) Monoamine oxidase 5) Cathecol-O-methyl transferase
Uptake 1 transport protein
What is pharmacokinetics?
What the body does to the drugs
What is pharmacodynamics?
What the drugs do to the body
What is a drug?
A chemical substance that interacts with a biological system to produce a physiological effect
What are the 4 drug target sites?
Receptors, ion channels, transport systems, enzymes - NB: ALL ARE PROTEINS
What are the receptors for drug target sites and what are they activated by?
Proteins within cell membranes, 4 types -> activated by NT/hormones
What is an agonist?
A molecule that stimulates the receptor causing the original action
What is an antagonist?
A molecule that blocks the receptor
How do ion channels allow drugs to target?
Has selective pores and allows transfer of ions down electrochemical gradients
How many types of ion channels and what are they?
2 -> Voltage sensitive (VSCC) and receptor-linked (nAChR)
What are some examples of receptor drugs?
ACh (agonist), atropine (antagonist)
What are some examples of ion channels drugs?
Local anaesthetics, Ca channel blockers
What are the transport system drug targets?
Transport against conc grad; with specificity for certain species