Lecture 8

Question 1

Explain parasympathoytic agents what is does and list 2 types and examples

Answer 1

parasympathoytic agents block nicotinic or muscarnic receptors by competitive antagonism there are 2 types (Anticholinergic drugs) -Antimuscarinic -Antinicotinc eg. atropine

Question 2

Explain the pharmacological effects of muscarinic antagonists

Answer 2

Pharmacological effects of muscarinic antagonists (shutting down rest and digest )

• rest and digest, if you block these receptors you will stop those effects you want to stop the rest and digest when you have things like diarrhoea and you can do this by giving atropine
• dose dependent inhibition of glandular secretions
• low doses will cause transient bradycardia due to action on CNS increasing vagal activity, @ higher dose= tachycardia, from decreased inhibition of pacemaker
• pupillary dilation
• relax smooth muscles therefore is the opposite of muscarinic receptor stimulation

Question 3

List some Clinical uses of Muscarinic antagonists

Answer 3

Clinical uses of Muscarinic antagonists;

pre-medicate for anaesthesia to stop bronchial and salivary secretions and prevent reflex of bronchoconstriction

• induction of pupil dilation and paralysis of accommodation (useful for looking at eye and treating it)
• spasmolytics for GIT, uterine, bronchial, smooth muscles etc.
• treament of acute asthmac attacks (using atropin by stopping parasympathetic part of bronchoconstriction)
• treatment of organophosphate poising, timing is important you can save the animal before 6 house because of the reactions is reversible then
• treating muscarine (mushroom poisoning)

Question 4

Discuss cholinesterase reactivates and antidotes

Answer 4

Cholinesterase reactivates and antidotes

• block muscarinic receptors reduce the parasympathetic effects, atropine is used
• use a selective antidote that dissociates the organophosphate from the enzyme, pralidoxime is the drug used for this

Question 5

Answer 5

what receptor subtypes are involved Cholinesterase will block the Ache receptors what are the organ function specific effects treatment options and rationales atropine apply early and 2 PAM

Question 6

Answer 6

A. atropine

Question 7

get photo

Answer 7

B. 2 PAM reactivties acetylcholinesterases

Question 8

Discuss Atropine toxicity and list clinical signs

Answer 8

Atropine toxicity; toxicity is dependent in species and route of admin; horses and ruminates are more susceptible

-herbivores more resistant to ingestion of belladonna leaves due to liver atronpinase,

most species are susceptible to atropine injected parentally signs include dry mouth

serve thirst

dysphagia

constipation

colic

mydrasis

tachycardia

cardiac arrhythmia’s hyperpnea ataxia

excitement followed by depression

-hot as hades, blind as a bat and dry as a bone

Question 9

Answer 9

C. Acetylcholine and Nicotine receptors

Question 10

Explain succinylcholine

Answer 10

succinylcholine ;These drugs are depolarisation and are resistance to hydrolysis and this causes paralysing skeletal muscle has a very short half life the muscles will come back to function if its the legs arms etc. if you use it for diagram and intercostal muscle to the point of no function this leads to death

Question 11

Discuss Autonomic ganglionic blockers

Answer 11

Autonomic ganglionic blockers which act on the parasympathetic system are muscarine and nicotinic receptor -receptor depolarising drugs eg. succinylcholine and nicotine -non-depolarising competitive drugs