Pharm 6

Question 1

What are the effects of a1 adrenergic receptors?

Answer 1

• vasoconstriction causing increased BP
• mydriasis (dilation of pupil)
• reduced GIT motility
• bladder sphincter contraction causing urinary retention

Question 2

What are the effects of a2 adrenergic receptors?

Answer 2

vasoconstriction and vasodilation

Question 3

What are the effects of B1 adrenergic receptors?

Answer 3

• increased myocardial contraction force + increased HR and increased CO
• detrusor muscle relaxation causing urinary retention

Question 4

What are the effects of B2 adrenergic receptors?

Answer 4

• bronchiolar dilation
• skeletal muscle vasodilation
• uterine relaxation

Question 5

What are the effects of adrenaline and when is it used?

Answer 5

• Mostly used in emergency
• Anaphylaxis – highly effective reducing effects of histamine - “physiological agonist” by reducing the effects of bronchoconstriction by B2 and also via B1 it reverse the effects of vasodilation
• Constant rate infusions (CRI’s) useful for dangerous hypotension – utilises a1 vasopressive effect to keep the blood pressure stable
• Control of minor bleeding through a1 important to realise this only affects arteriolar + capillary bleeding and does nothing for damage of larger vessels
• Added to other drugs to improve their efficiency – an example being its addition to local anaesthetics
• Cardiac arrest – B1 effect but cannot be used just by itself

Question 6

How is noradrenaline similar to adrenaline what is the practical implication of this?

Answer 6

• Similar to adrenaline but less substantial B2 effects. Can be used because the vet doesn’t want the B2 bronchodilation as it interferes with ability to get good blood pressure

Question 7

When are B2 agonists (Salbutamol and Salmeterol) used?

Answer 7

• B2 agonists given by aerosol for rapid relief of bronchiolar constriction. Works well when airway unpaired
• Salmeterol = the longer lasting of the two often given for equine airways

Question 8

When is B2 agonist Clenbuterol used?

Answer 8

• Injection or PO

* Respiratory system and also uterine relaxation (given in breach births in cows)

Question 9

What is the effect of Mixed agonist (Phenylpropanolamine)

Answer 9

• A1 effect is good at constricting the urethral smooth muscle (retaining of urine)
• B1 effect is relaxing of the detrusor muscle meaning improved bladder filling this helps with urinary incontinence

Question 10

What is the effect of the A2 drug Xylazine?

Answer 10

• A2 agonist having a sedative effect (Yohimbine a2 antagonist has reversing effects of Xylazine)

Question 11

What is the function of Propranolol & Atenolol?

Answer 11

• These act as “beta blockers” that act as antiarrthymias and vasodilators as a result of the negative effect on the excessive sympathetic stimulation of the heart a B antagonist effect

Question 12

What are the effects of muscarinic agonist Bethanecol?

Answer 12

Similar to Ach but is not degraded by cholinesterase. Used to increase detrusor muscle tone and promote urination. Effects of the CVS and the GIT are relatively mild.

Question 13

What is the effect of the Antimuscarinic Atropine?

Answer 13

Decrease salivation

Methiocarb toxicity

Question 14

When should atropine not be used?

Answer 14

Glaucoma

Question 15

When should the antimuscarinic tropicamide be used?

Answer 15

Ophthalmic examinations

Question 16

In the simplest terms what are the effects of parasympatholytic toxicity?

Answer 16

“Dry as a bone, red as a beet and mad as a hatter”