Cholinergic Antagonists. Flashcards
What are the effects of cholinergic antagonists?
They inhibit the actions of cholinergic receptors by blocking them.
What are the 3 classes of cholinergic antagonists?
Anti-muscarinic.
Ganglionic blockers.
Neuromuscular blockers.
What is the affect of anti-muscarinic blockers?
They block muscarinic receptors.
What is the affect of ganglionic blockers?
They block neuro-nicotinic receptors.
What is the affect of neuromuscular blockers?
They block muscular-nicotinic receptors.
What are 2 antimuscarinic agents?
Atropine.
Scopalamine.
What are the 6 modes of action of antimuscarinic agents?
Interaction with muscarinic receptor.
Prevention of ACH from binding.
Competitive antagonism.
Blockage of cholinergic effects so sympathetic action is dominant.
What sized dose of antimuscarinic agent is needed to create a vagolytic effect?
A large dose.
What are the effects of atropine on the cardiovascular system?
Tachycardia.
Increase in cardiac output.
Increase in blood pressure.
What are the effects of atropine on the GIT?
Relaxation of GIT.
Decreased motility.
Decreased secretions.
What are the effects of atropine on the urinary system?
Relaxation of bladder muscles.
Urinary retention.
What are the effects of atropine on the bronchioles?
Decreased secretions.
Bronchodilation.
What are the effects of atropine on the eyes?
Mydriasis (pupil dilation).
Cycloplegia.
Why should atropine not be given to animals suffering from glaucoma?
As it will increase ocular pressure.
What are the effects of atropine on the sweat glands?
Decreased secretion.
What are the effects of atropine on the CNS?
Minimal effects.
Hallucinations and excitement with large doses.
What is the therapeutic use of scopalamine?
Slight sedation.
Are herbivores or carnivores more sensitive to atropine?
Carnivores.
What animals are resistant to atropine?
Rabbits.
How do we test animals for atropine poisoning?
Urine test.
Look for mydriasis in a cats eye.
Pirenzipine is an antimuscarinic agent for what receptors?
M1 receptors.
What is the effect of pirenzipine?
It reduces gastric acid secretion.
What are the effects of telenzipine?
It inhibits M1 receptors and reduces gastric acid secretion.
What is the use of tropicamide?
It is used on the eye.
Gylcopyrrulate is used for what purposes?
As a pre-anaesthetic.
