Cholinergic and Adrenergic Pharmacology Flashcards
what are Cholinergic medications?
act upon the neurotransmitter acetylcholine, ACh and its receptors
what are Adrenergic medications?
bind to adrenergic receptors throughout the body. (these are (nor)adrenaline receptors)
describe structure of :
central ,
Peripheral,
somatic
autonomic,
sympathetic
parasympathetic nervous systems
nervous system has the CNS and PNS
PNS = all nerves outside brain and spinal cord
PNS has somatic and autonomic
autonomic has sympathetic (fight and flight) and parasympathetic (rest and digest)
main 2 differences between somatic and autonomic systems
somatic
- 1 neurone from CNS to muscle
- voluntary control of skeletal muscle
autonomic
- 2 neurones (pre an post ganglionic)
- involuntary control
what are the 2 areas of Parasympathetic nerve nuclei
DETAIL
brain: Cranial nerves 3,7,9,10 (remember 1973)
sacral outflow innervating the pelvis: at vertebrae T12-L1 and exit at S2-S4
what are the relative lengths of the pre and post ganglionic nerve fibres in the parasympathetic system?
Long preganglionic fibre (from spinal cord or brain to near organ target)
Short post ganglionic fibre (reach target and release acetylcholine, ACh)
where are the sympathetic ganglia?
in a chain beside the vertebrae
Sympathetic trunk along side vertebral canal from T1 to L2
what are the relative lengths of the pre and post ganglionic nerve fibres in the sympathetic system?
Short preganglionic fibres
synapse within trunk
Long post ganglionic fibres (to target)
what are the relative lengths of the pre and post ganglionic nerve fibres in the sympathetic system?
Short preganglionic fibres
synapse within trunk
Long post ganglionic fibres (to target)
what are the 2 main neurotransmitters?
Acetylcholine (Ach)
Noradrenaline (Nad)
Pregnalionic mediators:
which neurotransmitter acts on which receptors
is it different for para and sympathetic?
Ach acts on nicotinic receptors for both parasympathetic and sympathetic
Therefore both para + symp can be stimulated by nicotine SAME
Postganglionic mediators :
which neurotransmitter acts on which receptors
is it different for para and sympathetic?
Ach acts on muscarinic receptors in parasympathetic
Nad acts on alpha and beta receptors in sympathetic
what are 3 examples of exceptions to the Pregnalionic mediators and Postganglionic mediators trends?
Sweat glands have sympathetic postganglionic fibres that release ACh to stimulate muscarinic receptors
Nitric oxide is released from parasympathetic postganglionic termini in blood vessels
Multiple transmitters can be released at once to cause mixed effects (eg. ATP)
what are the 2 types of cholinergic receptors?
receptors ACh can act up on:
nicotinic
muscarninc
is Ach acting on nicotinic receptors a cholinergic reaction in the parasympathetic and/or sympathetic NS?
Nicotine stimulates both parasympathetic and sympathetic
is Ach acting on muscarinic receptors a cholinergic reaction in the parasympathetic and/or sympathetic NS?
parasympathetic nervous system
with the exception of sweat glands (sympathetic stimulation, but still ACh and muscanrinc receptors )
how many Muscarninc (M) receptors are there and how do they work?
5 types of M receptor,
all found on cell membrane and they active intracellular processes through G proteins
G proteins can activate various types of second messenger signals with different consequences for the cells
where are M1 receptors found?
brain
where are M2 receptors found?
if activated, in short, what happens
- SA node of heart (pacemaker)
- AV node of heart
activation decreases Heart Rate
where are M3 receptors found?
- reps tract
- GI tract
- skin
- urinary tract
- eyes
M3 receptors:
what does activation of M3 receptors in the respiratory tract cause?
reps tract –>
- bronchoconstriction (smooth muscle contraction in airways)
- produces mucus in airways and nasopharynx
M3 receptors:
what does activation of M3 receptors in the GI tract cause?
GI tract –>
increases saliva production, gut motility and biliary secretion
M3 receptors:
what does activation of M3 receptors in the skin cause?
skin –>
sweating
(sweat glands are sympathetic, therefore this is an exception)
M3 receptors:
what does activation of M3 receptors in the urinary tract cause?
urinary tract–>
contracts detrusor muscle + relaxes internal sphincter therefore you urinate
M3 receptors:
what does activation of M3 receptors in the eye cause?
eye –>
myosis (reduces pupil),
increases drainage of aq humour
causes secretion of tears
what is Muscarine poisoning ?
when the M receptors are activated inappropriately
eg. blurred vision, diarrhoea, bradycardia
which cholinergic drugs are used to treat glaucoma?
Pilocarpine eye drops
they are M3 agonists
Increases drainage of aqueous humour → reduces ocular pressure
which cholinergic drugs are used to treat AV node block?
Atropine -
dilates the pupils, increases HR
it is an antagonist, so blocks activation of M2 receptors in heart therefore prevents HR decrease
if tiotropium is an inhaled antagonist medication used to treat bonchoconstriction
a. what receptors is it acting on?
b. what side effects could result from acting on these receptors ?
a. treats bronchonconstriction by causing bronchodilation. therefore is an anti-muscarninc drug targeting M3 receptors
b. antagonist to M3 could cause
- dry mouth
- uriniary retention
- worsening existing glaucoma
what is ACh used for within the CNS?
what impact could anticholinergics therefore have in the CNS?
neurotransmitter involved in memory
therefore anticholinergics can causes memory problems and confusion
give examples of ACh outside the autonomic nervous system
- CNS, brain, memory
- somatic, causes flaccid paralysis in skeletal muscle, therefore cosmetic use (BoTox)
- ACh activates nicotinic receptors in somatic, therefore N1 blockers
give examples of ACh outside the autonomic nervous system
- CNS, brain, memory
- somatic, causes flaccid paralysis in skeletal muscle, therefore cosmetic use (BoTox)
- ACh activates nicotinic receptors in somatic
what receptors and neurotransmitters are involved in anaesthesia?
Ach uses N1 receptors in somatic NS (activates skeletal muscle)
therefore N1 blockers can cause muscle relaxation and therefore used as anaesthetics
what is the acronym SLUDGE used for? what does it stand for?
to help remember the common symptoms of certain affections of a cholinergic crisis (too much cholinergic):
“salivation, lacrimation, urination, defecation, gastrointestinal upset, emesis”.
briefly explain Ach movement at the synaptic cleft
chief neurotransmitter of the parasympathetic nervous system
ACh diffuses across the synaptic cleft and binds to receptors on the postsynaptic or the postjunctional membrane.
The binding of ACh to its receptors produces a conformational change in a membrane channel that is specifically permeable to both Na+ and K+.
ACh is concentrated at the synaptic cleft
within what NS, and on what receptors does noradrenaline activate?
Nad acts on alpha and beta adrenergic receptors in sympathetic NS
postganaglionic fibres
Nad. adrenaline and dopamine are all examples of what?
catecholamines
what are the different types of adrenoreceptors?
what type of reception are they?
2 alpha adrenoreceptors (alpha 1, alpha 2)
3 beta adrenoreceptors (beta 1,2,3)
G protein coupled receptors
what does the activation of alpha 1 receptors (by adrenaline or noradrenaline) cause?
vasoconstriction (especially in blood vessels and pupils and skin)
causes an increase in blood pressure and cardiac work
give a use of adrenaline and a use of noradrenaline medication
adrenaline will raise BP therefore used to treat anaphylaxis
noradrenaline given for IV shock
what does the activation of alpha 2 receptors (by adrenaline or noradrenaline) cause?
where are alpha 2 receptors found?
has mixed effects on smooth muscle
lowers blood pressure, reduced vascular tone
found in brain and peripherally
what could alpha 1 antagonists be used for?
block the increase of blood pressure
therefore can be used to treat hypertension
what does the activation of beta 1 receptors (by adrenaline or noradrenaline) cause?
where are they found?
Heart, kidney, fat cells
activation will increase heart rate and chronotropic effects
causes lipolysis and hyperglycaemia (to assist flight/flight)
what does the activation of beta 2 receptors (by adrenaline or noradrenaline) cause?
relaxes smooth muscle
what can beta 2 agonists be used for?
treat asthma
delay onset of premature labour
however are side effects eg. risk of arrhythmias
what does the activation of beta 3 receptors (by adrenaline or noradrenaline) cause?
relaxes bladder detrusor muscles
enhances lipolysis
what can beta 3 agonists be used for?
reduce over-active bladder symptoms
what can beta blockers be used for?
to treat hypertensions, heart failure, angina
what condition of patient would make you weary to prescribe beta blockers?
asthmatic patients
beta agonists are bronchodilators therefore blockers can cause constriction
what are side effects of beta blockers?
Tiredness
Bronchoconstriction
Bradycardia
Cardiac depression
