Lecture 6 - Cholinergic Agonists Flashcards
______ receptors use ion channels
nicotinic
nicotinic affects ganglion of both ___ and ___
SNS
PNS
nicotinic affects _____ muscle
skeletal
Muscarinic receptors are _____ mediated
G-protein
What do muscarinic receptors affect ?
effector organs/tissues of parasympathetic
Sweat receptors on the ____ are adrenergic
palms
Sweat receptors everywhere else are ____
cholinergic (but still part of sympathetic system)
All preganglionic synapses are _____
cholinergic
Skeletal muscle works through ___ receptors
ACh
Does ACh cross the BBB
NO
-so there are no psychological effects
What does ACh activate?
- all autonomic ganglia (sympathetic and parasympathetic)
- skeletal muscle receptors
What does Pilocarpine do?
-very similar to ACh but it CAN penetrate BBB
What is pilocarpine the drug of choice for?
severe acute glaucoma (intraocular pressure)
-it causes immediate opening of drainage system of the eye
-also used for fixed focus
What does AChE do? (acetylcholinesterase)
degrades Ach in the synapse
What will inhibition of AChE do?
It will increase the activity of ACh in the synapse
i. e. it will have a cholinergic agonist effect
- increased activation of the parasympathetic NS
What is myasthenia gravis?
it is autoimmune destruction of Ach receptors at NMJ (neuromuscular junction)
What type of drugs can help with myasthenia gravis?
drugs which increase ACh activity can aid the symptoms
(no underlying pathology)
- this is a short term solution because you are only increase Ach of the receptors that are left
- eventually all receptors will die because that is a characteristic of this condition
What is alzheimer’s disease?
cholinergic neurons in brain undergo reduced activity and then die
How can you treat alzheimer’s disease?
You can administer drugs which can increase ACh activity in the brain can therefore treat some symptoms of AD, but not underlying pathology
Neostigmine is a ??
AChE inhibitor
How does neostigmine work?
- stimulates the bladder and GI tract (used for urinary bladder disease and constipation)
- it can also aid in symptoms of myasthenia gravis (it increases muscular strength and response)
Donepazil (Aricept) is a ?
AChE inhibitor
How does Donepazil (Aricept) work?
stimulates cholinergic neurons in brain
-can be used to treat symptoms of alzheimer’s disease
Atropine is a ??
cholinergic antagonist
an antagonist of the parasympathetic nervous system
Atropine = ____
belladonna (beautiful woman)
-pupil dilation
Atropine does what?
-decreases CV response to parasympathetic stimulation
(heart rate increases and BP rises)
-bronchodilation and decreased respiratory sections
-antispasmodic effect on GI tract and other smooth muscles
-PUPIL DILATION
Neocitran is a ??
- antihistamine
- sympathomimetic
Neocitran is an antihistamine and therefore ?
decreases parasympathetic nerve activity
What are a few side effects of antihistamine?
-sedation and drying (atropinic)
What does a sympathomimetic do?
obvs increase sympathetic receptor activity
Who should not be taking Neocitran?
elderly people
- can cause cardiovasculation issues (hypertension, MI)
- can cause GI and GU issues (constipation and urinary retention)
Scopolamine
- strong CNS effect
- most-effective anti-nausea drug
Tiotropium
- derived from atropine
- inhaled bronchodilators (long-term effect)
What are some overdose/side effects of blocking cholinergic system
Eyes:
- sandy eye syndrome
- loss of near vision
Mouth:
-dry pasty saliva
Gut:
-no movement, but sustained acid - causes nausea, vomiting, constipation, pain
No Sweat:
Bladder: flaccid bladder, constricted sphincter
But you won’t care - cause you’re paralyzed
SLUDS
salivation lacrimation urination defecation sweat
Jimson weed
datura stramonium
Main ingredients: belladonna alkaloids, atropine, scopolamine
- anticholinergic
- extracts of it used in treating asthma, intestinal cramps, diarrhea and bed-wetting
red as a beet
dry as a bone
blind as a bad
mad as a hatter
What are NMJ blockers used for?
used in surgery
-it reduces the amount of anesthesia needed, allows rapid recovery of senses
-they are injected IV
What is the order of muscular paralysis?
eyes, face, fingers, limbs, trunk, diaphragm
Order of recovery from muscular paralysis?
diaphragm, trunk, limbs, fingers, face, eyes
NMJ blockers can be…?
non-depolarizing or depolarizing
How can NMJ blockers cause paralysis?
it desensitizes
-therefore a risk of paralysis
Curare is ??
an NMJ blocker
- it is amazonian poison
- no longer used
Is curare non-depolarizing or depolarizing?
non-depolarizing
Succinylcholine is ??
an NMJ blocker
-causes twitching and fasciculation at first (from depolarization) but then flaccid paralysis
Is succinylcholine non-depolarizing or depolarizing?
depolarizing
*only depolarizing NMJ used
